Brazilian Agricultural Research Corporation

Embrapa Soils

Ministry of Agriculture, Livestock and Food Supply

Brazilian Soil
Classification System

5th edition
revised and expanded

Embrapa

Brasília, DF

2018

Originally publised in Brazil as Sistema Brasileiro de Classificação de Solos by Embrapa, in 2018.

Copies of this publication can be purchased from:

Embrapa Soils

Rua Jardim Botânico, 1024

CEP 22460-000 Rio de Janeiro, RJ

Phone: 0055 (21) 2179-4500

www.embrapa.br | www.embrapa.br/fale-conosco/sac/

Publications Committee of Embrapa Soils

President: Vinicius de Melo Benites

Executive Secretary: Jacqueline Silva Rezende Mattos

Members: Ademar Barros da Silva, Adriana Vieira de Camargo de Moraes, Bernadete da Conceição Carvalho Gomes, Enyomara Lourenço Silva, Evaldo de Paiva Lima, Joyce Maria Guimarães Monteiro, Luciana Sampaio de Araujo, Maria Regina Capdeville Laforet, Maurício Rizzato Coelho, Moema de Almeida Batista, Ricardo de Oliveira Dart, Wenceslau Geraldes Teixeira

Editorial oversight: Jacqueline Silva Rezende Mattos

Bibliographic citations: Luciana Sampaio de Araujo

Graphic design and electronic editing: Marcos Antônio Nakayama

Cover: Eduardo Guedes de Godoy

Translation: Cornelia Elisabeth Abreu-Reichart (paratexts, chapters 1-4, 18, 19 and appendices) and Maria da Conceição Alves (chapters 5-17)

Revision: Cornelia Elisabeth Abreu-Reichart, Lúcia Helena Cunha dos Anjos, Humberto Gonçalves dos Santos, José Francisco Lumbreras.

1st edition

1st printing (1999): 1000 copies

2nd printing (2000): 1000 copies

3rd printing (2000): 1000 copies

4th printing (2001): 1000 copies

5th printing (2002): 1000 copies

6th printing (2003): 1000 copies

2nd edition

1st printing (2006): 2000 copies

2nd printing (2008): 2000 copies

3rd printing (2009): 2000 copies

4th printing (2010): 2000 copies

5th printing (2011): 2000 copies

3rd edition

1st printing (2013): 2000 copies

2nd printing (2017): 3000 copies

4th edition

E-book (2014)

5th edition

1st printing (2018): 3000 copies

E-book (2018)

All rights reserved

Unauthorized reproduction of this publication, in whole or in part, constitutes copyright infringement (Law no. 9,610).

International Cataloging in Publication (CIP) data

Embrapa Soils

Brazilian Soil Classification System / Humberto Gonçalves dos Santos … [et al.]. – 5. ed., rev. and exp. – Brasília, DF: Embrapa, 2018.

E-book : il. color.

ISBN 978-85-7035-821-9

1. Soil Classification. 2. Nomenclature. 3. Pedology. I. Santos, Humberto Gonçalves dos. II. Jacomine, Paulo Klinger Tito. III. Anjos, Lúcia Helena Cunha dos. IV. Oliveira, Virlei Álvaro de. V. Lumbreras, José Francisco. VI. Coelho, Maurício Rizzato. VII. Almeida, Jaime Antonio de VIII. Araújo Filho, José Coelho de. IX. Oliveira, João Bertoldo de. X. Cunha, Tony Jarbas Ferreira. XI. Embrapa Soils.

CDD 631.44

Luciana Sampaio de Araujo (CRB 7/5165)

©Embrapa, 2018

Authors

Humberto Gonçalves dos Santos

Agronomist, doctor in Soil Science, researcher at Embrapa Soils, Rio de Janeiro, RJ

Paulo Klinger Tito Jacomine

Agronomist, doctor honoris causa in Soil Genesis, Morphology and Classification, professor at the Federal Rural University of Pernambuco (UFRPE), Recife, PE

Lúcia Helena Cunha dos Anjos

Agronomist, doctor in Soil Science, full professor at the Soils Department, Federal Rural University of Rio de Janeiro (UFRRJ), Seropédica, RJ

Virlei Álvaro de Oliveira

Agronomist, doctor in Geoscience and Environment, researcher (retired) from the Brazilian Institute of Geography and Statistics (IBGE), Goiânia, GO

José Francisco Lumbreras

Agronomist, doctor in Environmental Planning and Management, researcher at Embrapa Soils, Rio de Janeiro, RJ

Maurício Rizzato Coelho

Agronomist, doctor in Soil Science, researcher at Embrapa Soils, Rio de Janeiro, RJ

Jaime Antonio de Almeida

Agronomist, doctor in Soil Science, professor at the Santa Catarina State University (UDESC), Lages, SC

José Coelho de Araújo Filho

Agronomist, doctor in Geochemistry and Geotectonics, researcher at Embrapa Soils, Recife, PE

João Bertoldo de Oliveira

Agronomist, doctor in Soils and Plant Nutrition, researcher (retired) from the Agronomic Institute of Campinas(IAC), Campinas, SP

Tony Jarbas Ferreira Cunha

Agronomist, doctor in Soil Science, researcher at Embrapa Semiarid, Petrolina, PE

We gratefully acknowledge the institutions of education, research and planning and the Brazilian pedologists, for contributing with suggestions, comments and criticism throughout the development of the Brazilian Soil Classification System.

In memoriam

Marcelo Nunes Camargo

Marcelo Nunes Camargo graduated in Agronomy from the Federal Rural University of Rio de Janeiro (UFRRJ), became doctor and lecturer in Soil Formation and Classification at the UFRRJ, graduated in Soil Morphology and Genesis from the North Carolina State University (USA), worked as a researcher at the National Service of Soil Survey and Conservation (nowadays Embrapa Soils) of the Brazilian Agricultural Research Corporation (Embrapa), as associate professor at UFRRJ, and was the winner of the Moinho Santista award in the area of Agrarian Sciences (category Agricultural Soils) in 1994. His entire life was dedicated to studies on soil morphology, classification, correlation and mapping. On the way to becoming the greatest exponent of pedology of tropical soils, he coordinated the research efforts that culminated in the publication of the Soil Map of Brazil, in 1981.

This page is a tribute and, at the same time, a public expression of gratitude for the outstanding services rendered to Brazil in the field of Pedology, by the unforgettable companion who, until the last days of his life, was devoted to the task of consolidating the Brazilian Soil Classification System.

Presentation

Embrapa Soils, a unit of the Brazilian Agricultural Research Corporation (Embrapa), has the honor of presenting to the society and, in particular, to the community of Soil Science, the 5th edition of the Brazilian Soil Classification System (SiBCS).

This work is the result of the collective experience with Brazilian soils, involving cooperators at different national research and teaching institutions, under the leadership and coordination of Embrapa Soils. The organizational framework consists of a National Executive Committee, assisted by regional collaborators and local discussion groups of the areas of soil genesis, morphology and classification.

Embrapa Soils was trusted with the coordination of this work, which included the role of articulating the necessary actions to facilitate the achievement of the proposed objective. The Executive Committee, whose members are the authors of this publication, is committed to the evaluation, consolidation, organization and final editing of the document.

Apart from the great and commendable effort required to overcome the inherent difficulties of the development of a proper classification system for Brazilian soils, and aside from the difficulties of geographic access and human and financial resources, boldness and courage were needed to believe that there were already enough highly educated and trained scientists in the Country to investigate, understand and organize the knowledge about tropical soils. The diversity and peculiarities of these soils were not fully covered by the existing systems, developed for other climatic and terrain conditions. From the first systematic soil surveys conducted in Brazil in the 1950’s and 1960’s, which gave rise to the current SiBCS, Dr. Marcelo Nunes Camargo as the leader, and another important collaborator, Dr. Jakob Bennema (Wageningen University, Netherlands) stood out as the researchers most dedicated to this topic. In the following years, the work was pursued by many scientists and teachers, based at their respective institutions throughout the Country, who were committed to the study and deeper understanding of the subject "soil classification". Several of the participants are members of the local groups of discussion and collaboration, to whom we extend our appreciation, on behalf of all who contribute to Pedology in Brazil.

In spite of challenging moments in the 1980’s and 1990’s, Pedology is now regaining the interest of society, in Brazil and worldwide, in view of the unquestionable importance of the soil resource for all matters related to food, fiber and energy production and to climate change and environmental sustainability. Thus, knowing the soils to improve their management by optimizing the application of sustainable agronomic practices, as well as for land use planning by means of zoning, has become imperative, not least for the definition of public policies.

It is worth noting that the ideas and proposals resulting from the Soil classification and correlation meetings in the field (RCCs), in which soil scientists from all across Brazil take part, are implemented under the lead management of Embrapa Soils and partners. The results of these meetings and other suggestions and criticisms posted on the website of the SiBCS¹, by users who have been applying the SiBCS since 1999 (1st edition), were assessed by the Executive Committee. Many of them, in the case of consensus, were integrated into the SiBCS. Thus, since the 4th edition of the SiBCS, two RCCs took place (in Roraima and Rondônia), which contributed significantly to the improvement of the system. The organization of these RCC meetings was enabled by strategic and financial support of Embrapa and other teaching and research institutions, as well as by financial support of science funding agencies, such as the National Council for Scientific and Technological Development (CNPq) and the Brazilian Federal Agency for Support and Evaluation of Graduate Education (CAPES).

The elaboration of the SiBCS, involving several educational and research institutions throughout Brazil, constitutes a clear example of a successful partnership, which resumed this issue as a national project, of interest and responsibility of the community of Soil Science in Brazil. Today, the SiBCS has nationwide coverage and is being taught in courses of Agrarian Sciences and others at all Brazilian universities, aside from being the subject of one of the best-selling books of Embrapa.

In this 5th edition, the hierarchical system of classification of the SiBCS is maintained, in an attempt to consolidate the taxonomic systematization, with a view to expressing the knowledge for the discrimination of soil classes identified in the Country. The alterations in this edition in relation to the previous involve from changes in criteria and concepts of horizons to the incorporation of soil classes into the categorical levels of suborders, great groups, subgroups and families. However, the Pedology and soil classification, due to their inherent scale-dependent nature, are not complete per se. In fact, the systematization in the current form is still in progress, due to the existence of to-date unknown soils in the Country (and which may justify the inclusion of new classes at different categorical levels of the system) and to the intrinsic nature of any classification system, evolving and adapting to advances in Soil Science, with the insertion of new classes and modifications of the former, to the extent to which new scientific knowledge is generated.

Therefore, users are invited to continuously test and apply the SiBCS and send in suggestions and criticisms, so that the publishers of new improved editions of the Brazilian system can count on enough material.

We take this opportunity to express our sincere congratulations to the pioneer and current researcher generations dedicated to soil classification in Brazil, for their efforts in developing knowledge on the subject.

José Carlos Polidoro

Chief of staff ad interim of Embrapa Soils

Notes

(1) Available at: <http://www.embrapa.br/solos/sibcs>.

Note of the Executive Committee

In this edition, the general structure of the Brazilian Soil Classification System (SiBCS) was maintained, incorporating changes, redefinitions and corrections. The system is released for use and may be cited and correlated with others.

This work will be enhanced over the course of the coming years, as a result of the effective application in soil surveys, soil correlation studies and research in the area of Soil Science.

The amendments proposed here were made available for testing and validation by the users (Santos et al., 2016, 2017) and presented in part at the Brazilian Congress of Soil Science, 2017. They include from basic definitions and concepts to the restructuring of classes at all categorical levels. These changes are responses to suggestions and criticism expressed by users of the SiBCS and, in particular, to the ideas and proposals brought up at the last seven meetings of soil classification and correlation (RCCs) in the South, Southeast and North regions of the Country (Reunião..., 2000, 2005, 2008, 2010a, 2010b, 2012, 2013, 2015, 2017). The RCCs have traditionally enabled the validation and improvement of the SiBCS, as well as the standardization of criteria, and the interinstitutional exchange and information transfer among Soil Science professionals.

The improvements consist of adjustments, corrections and redefinitions of basic concepts concerning the definition of soils; the argiluvic, aluminic and chromic qualifiers; lithic contact; fragmentary lithic contact; skeletal constitution; histic horizon and anthropic A horizon. Changes in wording, redefinitions of the control section, and the elimination or incorporation of soil classes are proposed at the categorical levels of orders (Gleissolos, Nitossolos, Organossolos, Vertissolos); of suborders (Argissolos Vermelhos, Cambissolos Hísticos, Chernossolos Argilúvicos, Neossolos Litólicos, Neossolos Regolíticos, Planossolos Nátricos); in the great groups (inclusion of the Psamíticos in the Neossolos Regolíticos, redefinition of the Psamíticos in the Neossolos Flúvicos, exclusion of Distroúmbricos and Eutroúmbricos from the Neossolos Litólicos and Neossolos Regolíticos, exclusion of Alíticos from various suborders, creation of Hísticos and exclusion of Húmicos from Gleissolos Tiomórficos); and in the subgroups (inclusions of many soil classes, exclusion of úmbricos, redefinition of chernossólicos, creation of the espesso-húmicos – Latossolos and Neossolos Quartzarênicos – and of the leptofragmentários – Argissolos, Cambissolos, Chernossolos, Gleissolos, Neossolos Regolíticos, Neossolos Quartzarênicos, Nitossolos, Organossolos and Plintossolos –, and the replacement of the term êndicos by mésicos at the 4th categorical level of Planossolos); as well as at the categorical level of families (for example with the creation of ândicos) and of series. Also presented are soil depth classes, soil reaction classes and a proposal for the designation of land types.

The previously defined subgroups in the SiBCS can be used in other great groups, in which their occurrence has not been included. In these cases, an explanation and a copy of the profile should be submitted for the evaluation and validation of the new class. Proposals of new classes at any categorical level should be sent to the Executive Committee of Soil Classification (CE), containing a justification for the proposed inclusion and a copy of the corresponding profile for evaluation and validation, so that this new class can be officially incorporated into the system.

When classifying a given soil profile, the classifier is allowed to make combinations of descriptors at the 4th level, provided that they were already defined in the SiBCS for any great soil group. At most three descriptors may be used at this categorical level, for example, Argissolo Vermelho Eutrófico solódico abrúptico plintossólico (see Chapter 5, Argissolo...).

This edition substitutes the soil classification previously used by Embrapa Soils (Camargo et al., 1987; Sistema..., 1999; Santos et al., 2006, 2013, 2014) and all previous approximations (Sistema..., 1980, 1981; Camargo et al., 1988a; Carvalho et al., 1997).

With a view to the continuous upgrading of the SiBCS, as a result of the scientific development and increased knowledge about Brazilian soils, users are asked to send periodic criticism and suggestions, which should be forwarded to the EC SiBCS (at <cnps.sibcs@embrapa.br>), where new updates can be permanently accessed on the SiBCS website².

It is also worth emphasizing that the SiBCS, gradually constructed by the Brazilian scientific community over decades, is now structured in the form of a taxonomic key up to the 4th categorical level, with recommendations of qualifiers/properties to be applied in the soil classification at the 5th categorical level (family). Nevertheless, even in the current state, the SiBCS already meets nearly all demands currently known in Brazil with regard to soils.

The suggestions of characteristics/properties for the 6th categorical level are of preliminary nature. Their implementation will require a major volume of specific information from and organizational support in the Country.

Notes

(2) Available at: <http://www.embrapa.br/solos/sibcs>.

History of development of the Brazilian Soil Classification System³

The classification of the soils of Brazil has been a matter of interest, primarily motivated by the demand arising from soil surveys, which, by nature, are a type of research that calls for soil classification.

The national pedological classification in effect is the result of the development of the former American system, formulated by Baldwin et al. (1938) and modified by Thorp and Smith (1949). This classification, which was nationalized in Brazil, is essentially based on the core concepts of the American system, in spite of relying on the additional support of clarifying explanations of concepts and criteria established in a number of key publications, in particular those of the authorship of: Kellogg (1949) and Kellogg and Davol (1949), about Latossolos; Simonson (1949), concerning the Podzólicos Vermelho-Amarelos; Winters and Simonson (1951) and Simonson et al. (1952), with regard to several great groups of soils; United States (1951), addressing the Solos Glei and Solos Salinos and Alcalinos; Tavernier and Smith (1957), about Cambissolos; and of Oakes and Thorp (1951), on Rendzinas and Vertissolos (Grumossolos). The central concepts of the former American system represent the basis of the current transmuted Brazilian classification. The current layout was shaped by modifications of criteria, alterations of concepts, creation of new classes, dismemberment of some original classes, and the formal recognition of subclasses of intermediate or transitional nature. The process of modification was constantly directed to aggregate modifications according to the emerging requirements, based on intermediate and small-scale surveys, in which classes of higher hierarchical categories were compared with each other. The main focus was always the hierarchical level of great soil groups, coupled with the exercise of creative tests at the subgroup level, since classes in this category had never been established in the primitive system (Baldwin et al., 1938; Thorp; Smith, 1949).

The modifications were initiated in the 1950’s, with the first soil surveys conducted by the then Soil Commission of the National Center for Education and Agronomic Research (CNEPA). They were intensified by the end of that decade, with the extensive testing of principles that were being recognized parallel to the approximations to the new American system of soil classification. This framework was being developed at the time (United States, 1960), giving rise to the Soil Taxonomy, the official classification currently in force in the country (United States, 1975, 1999). Many concepts arising from the release of this new system were absorbed in the classification in use in Brazil. Similarly, some concepts and criteria laid down in the reference bases of the Soil Map of the World (FAO, 1974) and the WRB (IUSS Working Group WRB, 2015) were also assimilated in the development of the national classification.

In the soil survey of the state of São Paulo (Lemos et al., 1960), distinctive pedogenetic horizons, specific of certain soils, were recognized as legitimate diagnostic criteria to establish and define soil classes in the natural system of classification. On this occasion, the concepts of latosolic B and textural B horizons were used for the first time in Brazil.

Additional contributions to the Brazilian pedological classification came from basic research in soil surveys of the above system, namely the conceptualization of Latossolos and the tentative subdivision of classes of Latossolos as a result of the observed variations (Latossolo Roxo, Latossolo Vermelho-Escuro, Latossolo Vermelho-Amarelo, Latossolo Vermelho-Amarelo Húmico); the creation of the Terra Roxa Estruturada class; and the subdivision of Solos Podzólicos, mainly due to the textural distinctions between soils, expression of the textural B horizon in the profile, extraordinary textural contrast between the eluvial and the textural B horizons and, above all, the high base saturation in the textural B or even in the solum, a condition that had not been clarified until then in the classification of tropical Solos Podzólicos.

The soil survey carried out in the south of Minas Gerais (Camargo et al., 1962) however recognizes the incipient B horizon, diagnostic for the class that included the Solos Brunos Ácidos – precursor of the Cambissolos.

Thereafter, the soil surveys carried out by the Commission of Soils and successor institutions demanded adaptations for soils as they were being identified, especially with regard to the diversity of attributes and the variability in soil morphology and constitution. Consequently, modifications and additions were included, involving adjustments and innovations in differentiating criteria, resulting in the standards compiled by Carvalho et al. (1988).

Thus, initial divisions of great groups were eventually established, based on distinction by base saturation, activity of clays as expressed in the cation exchange capacity of inorganic colloids, sodium saturation, presence of calcium carbonate, abrupt textural change to the B horizon, and by other distinctive features.

The collection of criteria also included various diagnostic attributes for several types of A horizons, B horizons and other diagnostic horizons in variable positions in soil profiles, which were integrated over the course of the development of the new American system of pedological classification (United States, 1960, 1975, 1999, 2009) and of the reference bases of FAO (1974, 1990) and WRB (IUSS Working Group WRB, 2015).

Several soil classes of high categorical levels were included to incorporate the classification of expressively distinct soil types, which were identified during soil surveys conducted in the wide diversity of climatic, geomorphic, vegetational and geological ambiences of the national territory.

Another contribution to the system resulted from a study of soil reexamination, when in the Southern region of the Country, on the highlands of Curitiba, soils sui generis were identified, leading to the proposal of the Rubrozém class (Bramão; Simonson, 1956).

Also in the 1950’s, the class of Hidromórficos Cinzentos (Barros et al., 1958) was recognized, derived from Planossolos and Gleis Pouco Húmicos of the American system, then in effect (Baldwin et al., 1938; Thorp; Smith, 1949).

Subsequently to the distinction of the classes of Latossolos Roxos, Latossolos Vermelho-Escuros and Latossolos Vermelho-Amarelos, also described in the cited survey of the State of São Paulo, other classes were added: establishment of Latossolos Amarelos, based on studies of Day (1959) and Sombroek (1961) in the Amazon; Latossolos Brunos, identified by Lemos et al. (1967) in Rio Grande do Sul; Latossolos Variação Una, first reported in 1963 in the south of Bahia (Jacomine et al., 1977-1979); and Latossolos Ferríferos, as conceptualized by Camargo (1982). With respect to the distinction of Latossolos, Camargo et al. (1988b) are accredited with the classification of these soils in the Country.

Areias Quartzosas constitutes a soil class recognized since the beginning of the 1960’s (Lemos et al., 1960) as independent group, dismembered from the Regossolos – a class that became less extensive by the exclusion of those quartzose soils – defined as weakly developed soils because of the very refractory nature of the quartz-rich material, resulting in low pedogenetic development.

A modification of the concept at the beginning of the 1970’s, in response to observations of soils identified in several field investigations, substantiated the class of Solos Litólicos (Freitas et al., 1971; Jacomine et al., 1972-1973).

In the pedological survey of Ceará, Solos Podzólicos were observed with peculiar and atypical characteristics in relation to original conceptions of classes established in these soils, which led to the recognition of the class of Podzólicos Acinzentados (Jacomine et al., 1973).

Similarly, other atypical Solos Podzólicos, formed in the upper part of the Barreiras Formation (and related areas), as a counterpart to Latossolos Amarelos, led to the proposal of the class of Podzólicos Amarelos (Reunião..., 1979a).

Soils that are hard to identify, seen as similar to Terra Roxa Estruturada (however, differentiated by the color related to the oxidic constituents), were found in the Southern region, and their discrimination was considered with the definition of the class of Terras Bruna Estruturadas (Carvalho et al., 1979; Carvalho, 1982).

The class of Plintossolos was established at the end of the 1970’s (Jacomine et al., 1980), as a result of years of reflection about the validity of the current conceptualization of Plintossolos as a separate class in the referential system. A large part of this class assembles the various soils of the former class of Lateritas Hidromórficas, including part of the soils of some other classes, defined before the Plintossolos.

The last major addition to the referential system was the class of Podzólicos Vermelho-Escuros (Camargo et al., 1982), which is a separate group of soils distinct from the traditional class of Podzólicos Vermelho-Amarelos. The placement of this new class is homologous to that of the other Solos Podzólicos and represents a counterpart to the Latossolo Vermelho-Escuro. The established class includes a part of the soils removed from the class of Podzólicos Vermelho-Amarelos and includes all soils of the excluded Terra Roxa Estruturada Similar.

These were important changes that influenced the progression of the soil classification in the sense of its nationalization, now implemented by the four approximations developed from 1980 to 1997 and by the publication of the Brazilian Soil Classification System (Sistema..., 1998, 1999; Santos et al., 2006, 2013, 2014). The correlation between the soil classes of the SiBCS (current edition) and those used before in Brazil, until the publication of the 1st edition (1999), is shown in Appendix I.

This edition of the SiBCS contains relevant changes, from the order level to the family level, with redefinitions, restructuring, exclusion and inclusion of classes, which were discussed and approved by the Executive Committee of Soil Classification (Santos et al., 2003, 2009, 2012, 2016, 2017).

Notes

(3) Adapted from Jacomine and Camargo (1996).

List of acronyms

ADFE

Air-dried fine earth fraction

Ald

Aluminium extracted by a dithionite-citrate-bicarbonate solution

Alo

Aluminium extracted by an acid ammonium oxalate solution

CAPES

Brazilian Federal Agency for Support and Evaluation of Graduate Education

CEC

Cation exchange capacity

CNEPA

Soil Commission of the National Center for Education and Agronomic Research

CNPq

National Council for Scientific and Technological Development

COLE

Coefficient of linear extensibility

Db

Bulk density

Dbi

Bulk density of the initial soil or soil in its original state

Dbr

Density of residual soil

DCB

Dithionite-citrate-bicarbonate

Dom

Organic matter density

Dp

Particle density

EC SiBCS

Executive Committee of Soil Classification

EC

Electrical conductivity

Embrapa

Brazilian Agricultural Research Corporation

Fed

Iron extracted by a dithionite-citrate-bicarbonate solution

Feo

Iron extracted by an acid ammonium oxalate solution

HIS

Hydroxy-Al interlayered smectite

HIV

Hydroxy-Al interlayered vermiculite

PI

Pyrophosphate index

IUSS

International Union of Soil Sciences

m

Aluminum saturation

MM

Mineral material

MR

Minimum residue

MU

Mapping unit

OC

Organic carbon

ODFE

Oven-dried fine earth fraction

OM

Organic matter

OMl

Organic material

RCC

Soil classification and correlation meetings

S value

Sum of bases

SBCS

Brazilian Society of Soil Science

SI

International System of Units

SiBCS

Brazilian Soil Classification System

SOM

Soil organic matter

Ta

High activity clay

Tb

Low activity clay

Tm

Medium activity clay

Tmh

Moderately high activity clay

Tml

Moderately low activity clay

Tvh

Very high activity clay

Tvl

Very low activity clay

V value

Base saturation

Wg

Gravimetric moisture

WRB

World Reference Base for Soil Resources

XRD

X-ray diffraction

Introduction

The Brazilian Soil Classification System (SiBCS) is the official taxonomic system of soil classification of Brazil. It is a national priority addressed by several educational and research institutions in the Country ever since the first attempts of organization in the 1970’s, based on successive approximations, seeking to define a hierarchical, multicategory and open system, that would allow the inclusion of new classes and make the classification of all soils across the national territory possible.

In the period between 1978 and 1997, the following approximations were established: 1st approximation (Sistema..., 1980), 2nd approximation (System..., 1981), 3rd approximation (Camargo et al., 1988a) and a 4th approximation (Carvalho et al., 1997), which all include discussions, organization, circulation of documents for criticism and suggestions, as well as dissemination, initially restricted, among participants and members of the scientific community, culminating in the publication of the 1st, 2nd, 3rd and 4th editions of the SiBCS (Sistema..., 1999; Santos et al., 2006, 2013, 2014), widely disseminated at the national and international level and adopted in Brazil.

The constant improvement of the SiBCS is a national project, of interest and responsibility of the Soil Science community in the Country, and is coordinated by Embrapa Soils. The foundation of the system relies on institutional partnerships, previous studies and the recent development of knowledge in the area of Soil Science.

The initial reference points for the 1st and 2nd editions were the 3rd approximation of the System (Camargo et al., 1988a) and the following publications: Soil map of the world (FAO, 1990), Référentiel Pédologique Français and Référentiel Pédologique (Association Française pour l'Étude du Sol, 1990, 1995), Keys to Soil Taxonomy (United States, 1994, 1998, 2006, 2010) and World Reference Base for Soil Resources (FAO, 1994, 1998, 2006). This edition of the SiBCS is, in the light of the knowledge and research generated in the Country and abroad (United States, 1999, 2014; Isbell, 1996, 2016; IUSS Working Group WRB, 2015), the result of a review and update of the parameters and criteria used in the 3rd and 4th editions (Santos et al., 2013, 2014) and of previous approximations, as well as the incorporation of suggestions and contributions received from the scientific community.

The project of development and validation of the SiBCS is generating actions at three levels of discussion and decision-making, involving organized inter-institutional groups at national, regional and local levels. Moreover, teams at universities, state or federal public institutions and/or private institutions have been working with soil surveys, on the elaboration of dissertations and theses and on other activities related to this subject.

The organizational framework related to the soil classification is currently overseen by the National Executive Committee, assisted by regional collaborators and local discussion groups of the areas of soil genesis, morphology and classification.

In the 1st edition of the SiBCS, 14 classes of the 1st categorical level were maintained as in the 4th approximation of the system. However, the concepts and definitions of most of the parameters and criteria used in the 4th approximation were largely modified. In the 2nd edition, only 13 classes of the 1st categorical level (orders) were maintained, as a result of the exclusion of the order of Alissolos, according to a proposal of system users and members of the National Advisory Committee and Regional Committees, which was discussed and approved by the Executive Committee. In this edition, the 13 classes of the 1st categorical level were maintained.

The classes of the 1st categorical level (orders) are presented alphabetically in Chapter 3 (Concept and definition of the classes of the 1st categorical level) and in Chapters 5 through 17. In Chapters 1 and 2, the definitions of some attributes and horizons were changed and some qualifiers included.

In Chapter 18, criteria and taxonomic attributes for the definition of classes of the 5th categorical level (families) are listed. The recommended criteria should be tested in the different soil classes, ensuring appropriate methodologies and responses in terms of agronomic and geotechnical relevance and for other purposes. The 6th categorical level is still in the discussion phase. For these categorical levels, research projects of the different institutions should be encouraged.

The majority of the appendices was maintained as in the 4th edition, but a few were updated, such as Methods of soil analyses adopted by Embrapa Soils (Appendix D), Symbology of the classes of the 1st, 2nd and 3rd categorical levels (Appendix E), Ordering of legends of soil identification (Appendix G), Standardization of the colors of the classes of the 1st and 2nd categorical levels for use in soil maps (Appendix H), and Approximate agreement between soil classes at high categorical levels in the SiBCS, WRB and Soil Taxonomy (Appendix J). In addition, the following appendices were inserted: Classes of soil depth (Appendix A), Classes of soil reaction (Appendix C) and Terrain types (Appendix F).

The definitions and notations of horizons and soil layers are used according to Carvalho et al. (1988) and the basic knowledge of morphological characteristics contained in the Súmula da Reunião Técnica de Levantamento de Solos (Reunião..., 1979b) and the Manual de descrição e coleta de solo no campo (Lemos; Santos, 1996; Santos et al., 2015). Throughout the text, the measures were used according to the Guide for the use of the International System of Units (SI) (Taylor, 1995).

Definition of soil

The soil we classify is a collection of natural bodies, consisting of solid, liquid and gaseous parts that are three-dimensional, dynamic, and consists of mineral and organic materials that occupy most of the surface crust of the continental dimension of our planet; it contains living matter and may be vegetated where it occurs in the nature and may possibly have been modified by anthropogenic interference.

An examination from the surface downwards shows that soils consist of roughly parallel sections, arranged in layers and/or horizons that are different from the original parent material, as a result of additions, losses, translocations and transformations of energy and matter that occur over the course of time and under the influence of factors of climate, organisms and relief. The horizons reflect the processes of soil formation by weathering of bedrock or sediments of diverse nature. The layers, in turn, are little or not at all affected by pedogenetic processes, maintaining, to a greater or lesser extent, the characteristics of the parent material.

The upper limit of the soil is the atmosphere, although some soils can have an overlying water column (permanent or periodic), provided that there is no barrier to the development of plant roots adapted to these conditions. The lateral limits are the contacts with surface water bodies, rocks, ice, areas covered by unconsolidated detrital material, landfills, or terrain under permanent water cover. The lower limit of the soil is hard to define. In general, the soil gradually gives way to hard rock in depth, or to saprolitic material or sediments with no signs of influence of biological activity. The underlying material (not soil) contrasts with the soil by the sharp decrease in organic constituents and the decrease of alteration and decomposition of mineral constituents, i.e., by the predominance of properties more related to the rocky substrate or to unconsolidated parent material.

The three-dimensional body that represents the soil is called pedon. The face of the pedon, involving from the surface to the contact with the parent material, constitutes the basic study unit of the SiBCS. This unit is the soil profile, evaluated in two dimensions on a minimal total area to enable the study of variability in the attributes, properties and characteristics of the soil horizons or layers.

Under the prevailingly humid tropical climate conditions in Brazil, the expression of the biological activity and the pedogenetic processes commonly reach depths > 200 cm. In these cases, mainly due to practical aspects of performing field work, the lower limit of the control section of the soil for the purpose of classification is arbitrarily fixed at 200 cm, except when:

The thickness of horizon A is > 150 cm. In this case, the arbitrary limit is 300 cm (situation sometimes observed in Argissolos and Latossolos); or

Horizon E is present in the sequum, and the thickness of the E added to that of the A horizon is ≥ 200 cm. In this case, exclusively for the classes of Espodossolos, the arbitrary limit is 400 cm.

For certain characteristics, attributes and/or soil properties, specific control sections are used for classification purposes. These control sections are defined in the keys for the identification of soil classes (Chapters 4–17). However, it is recommended, whenever possible, to reach a depth of 200 cm for profile descriptions of deep soils.

Chapter 1

Diagnostic attributes and other attributes

Diagnostic attributes

Organic material

This kind of material is derived from plant residues in different decomposition stages, exclusive of live roots, but including the finely divided charcoal fragments and biomass in the soil that result from natural processes. Organic material can be associated to mineral material, in varying proportions. However, it is regarded as organic if all of the following requirements are met:

The content of organic constituents must be high enough to ensure predominance of their properties over those of the mineral constituents; and

The organic carbon content must be ≥ 80 g kg⁻¹, measured in the air-dried fine earth fraction (ADFE), according to the method adopted by Embrapa Soils (see Appendix D).

Mineral material

This material consists predominantly of inorganic compounds in different weathering stages. A soil material is referred to as mineral if it does not meet the requirements for organic material (previous item).

This criterion was derived from United States (1999) and IUSS Working Group WRB (2015).

Activity of the clay fraction

The clay fraction activity refers to the cation exchange capacity⁴ of the clay fraction, without correction for carbon, and calculated as: T (cmolc kg⁻¹) x 1,000 / clay content (g kg⁻¹). A high clay activity (Ta) corresponds to ≥ 27 cmolc kg⁻¹ clay and a low activity (Tb) to < 27 cmolc kg⁻¹ clay. This criterion does not apply to soil materials with sand and loamy sand texture.

The distinction of classes by this criterion is based on the activity of the clay fraction in the B horizon (including BA and excluding BC) or in the C (including CA), when there is no B horizon.

This criterion was derived from United States (1999).

Base saturation⁵

This parameter indicates the proportion (percentage rate, V% = 100 x S/T) of exchangeable base cations in relation to the exchange capacity, determined at pH 7 (the S value corresponds to the sum of bases). The expression "high saturation" is used for soils with base saturation ≥ 50% (eutrophic) and "low saturation" defines soils with values < 50% (dystrophic). Additionally, V values of ≥ 65% are used for the identification of A horizons classified as chernozemic.

The distinction between soil classes is based on the base saturation in the subsurface diagnostic horizon (B or C). In the absence of these horizons, the application of the criterion is defined for each class.

In soils with high base saturation and simultaneously sodic and/or salic or saline qualifiers, the former is no indication of high fertility, because of the high sodium content and/or high soluble salt contents. In soils of the sand and loamy sand texture classes and with S values < 1.0 cmolc kg⁻¹, high base saturation is not related with high fertility either.

Abrupt textural change

This attribute consists of a drastic increase in clay content within a short distance in the transition zone between the A or E horizon and the underlying B horizon. When the A or E horizon has a clay content of < 200 g kg⁻¹ soil, the clay content of the underlying B horizon, determined at a vertical distance of ≤ 7.5 cm, should be at least twice as high as that of the A or E horizon. When one of these two horizons has a clay content of ≥ 200 g kg⁻¹ soil, the increase in clay in the underlying B horizon, determined at a vertical distance of ≤ 7.5 cm, must be ≥ 200 g kg⁻¹ in absolute values in the fine earth fraction (e.g.: 300 g kg⁻¹ to at least 500 g kg⁻¹, or 220 g kg⁻¹ to at least 420 g kg⁻¹).

This criterion was adapted from IUSS Working Group WRB (2015).

Plinthite

This formation consists of a mixture of clay, poor in organic carbon and rich in iron or iron and aluminum, with quartz grains and other minerals. It commonly occurs in the form of red, yellowish red and dark red mottles, usually with laminar, polygonal or reticulate patterns. In terms of genesis, plinthite is formed in humid environments by iron segregation, which comprises mobilization and transport and the final concentration of the iron compounds. This process can occur in any soil with a sufficiently high iron content to allow its segregation in the form of soft red materials.

Under natural conditions, a single wetting–drying cycle will not result in irreversible hardening of plinthite. In moist soil, plinthite is soft and can be cut with a knife or broken by hand.

Plinthite is a distinct body of iron oxide-rich material and can be differentiated from consolidated ferruginous nodules or concretions (petroplinthite), which are extremely firm or hard. Plinthite is firm when moist and hard or extremely hard when dry, with a diameter > 2 mm, and is separable from the soil matrix, i.e., from the surrounding material. It resists to moderate pressing and rolling between thumb and forefinger and can be broken by hand. Plinthite immersed in water for two hours does not disintegrate, even when shaken slightly periodically, but it can be broken or deformed after immersion in water for longer periods.

The colors of plinthite have hues between 10R and 7.5YR, with high chromas, and commonly contain yellowish brown and yellowish red mottles that are not considered plinthite, as well as brittle, friable or firm bodies that break when pressed between thumb and forefinger and crumble in water.

Plinthite can be found in laminar, nodular, spheroidal or irregular shapes.

This criterion was adapted from United States (1999), and Daniels et al. (1978).

Petroplinthite

This material is normally derived from plinthite, which, once exposed to repetitive wetting cycles followed by marked dryness, is subjected to strong consolidation, leading to the formation of ferruginous nodules or concretions (ironstone, lateritic concretions, canga, tapanhoacanga) of varying sizes and shapes (laminar, nodular, spheroidal or elongated). It may be arranged in the profile vertically or irregularly and separately or in agglomerates.

This criterion was derived from Sys (1967) and Daniels et al. (1978).

Friction surfaces (slickensides)

These polished and shiny surfaces, mostly strongly grooved, are a result of the shear and friction of the soil mass caused by motion due to the strong swelling of clay material upon wetting. The surfaces are typically inclined in relation to the verticality of the profiles.

This criterion was adapted from United States (1999) and Santos et al. (2015).

Acric qualifier

This qualifier is used to describe soils in which the sum of exchangeable bases (Ca²⁺, Mg²⁺, K⁺ and Na⁺) + aluminum extractable by KCl 1 mol L⁻¹ (Al³⁺) has values of ≤ 1.5 cmolc kg⁻¹ clay, and meets at least one of the following conditions:

pH KCl 1 mol L⁻¹ equal to or higher than 5.0; or

ΔpH positive or zero (ΔpH = pH KCl – pH H₂O). 

This criterion was derived from United States (1994) and IUSS Working Group WRB (2015).

Aluminic qualifier

This qualifier refers to the condition of a soil with an extractable aluminum content of ≥ 4 cmolc kg⁻¹ soil, aside from an aluminum saturation of [100 x Al+3 / (S + Al⁺³)] ≥ 50% and/or base saturation of (V% = 100 x S/T) < 50%.

To discriminate soils by this criterion, the extractable aluminum content of the B or C horizon (in the absence of B) is considered.

Argiluvic qualifier

This qualifier distinguishes soils with a significant clay concentration in the B horizon, but not high enough to identify a B horizon as textural or planic. This qualifier is defined by the simultaneous presence of:

A texture ratio (B/A) ≥ 1.4 (calculated by the same criteria to distinguish a textural B horizon, described in Chapter 2, subitem h); and

A B horizon with prismatic structure, with any degree of development, or blocky structure and at least an intermediate development degree.

Carbonatic qualifier

This property is given by a CaCO₃ equivalent content of ≥ 150 g kg⁻¹ soil under any form of segregation, in addition to nodules and/or concretions, as long as the requirements for a calcic horizon are not met.

This criterion was adapted from United States (1999).

Hypocarbonatic qualifier

This property refers to the presence of CaCO₃ equivalent under any form of segregation, in addition to nodules and/or concretions, of ≥ 50 and < 150 g kg⁻¹ soil. It discriminates soils that contain CaCO₃ in some horizon but are not carbonatic qualifiers.

This criterion was derived from the appendix of the Soil Survey Manual (USDA, 1951).

Cohesive qualifier

This qualifier is used to distinguish soils with dense pedogenetic subsurface horizons, which are very resistant to penetration with a knife or breaking with a hammer, are very hard to extremely hard when dry, and become friable or firm when moist. Under compression, moist samples are slowly deformed, opposite to fragipan, which is a brittle material (crumbles up into smaller fragments). The texture of these horizons is loamy clayey or very fine clayey, and under natural conditions, they have a weak structural organization, generally massive or tending to form blocks. The cohesive qualifier is commonly observed in the transitional AB and/or BA horizons at depths between 30 cm and 70 cm below the soil surface, and it can reach the Bw or coincide totally or partially with the Bt. A dry sample of a horizon that is cohesive will be dissolved when immersed in water.

This criterion was derived from Jacomine (2001), Ribeiro (2001) and Santos et al. (2015).

Concretionary qualifier

This term is used to define soils with petroplinthite in the form of nodules or concretions in one or more horizons within the control section that defines the class, but with insufficient quantity and/or thickness to be defined as a concretionary horizon. It must contain a minimum amount of 5% petroplinthite per volume.

Chromic qualifier⁶

This qualifier refers to the predominance of colors (moist samples) in most part of the B horizon, excluding BC, as defined below:

Hue 5YR or redder, with values ≥ 3 and chromas ≥ 4; or

Hue from yellower than 5YR up to 10YR, values ≥ 4 and chromas ≥ 4; or

Hue from yellower than 10YR to 5Y, values ≥ 5 and chromas > 4.

Duric qualifier

This qualifier is used to describe soils with strong cementation in one or more horizons within the control section that defines the class; it includes soils with duripan, ortstein, placic and other strongly cemented horizons that do not fall within the definition of lithoplinthic, concretionary and petrocalcic horizons.

Ebanic qualifier⁷

This qualifier indicates prevailingly dark, nearly black colors in most part of the diagnostic subsurface horizons, as defined below:

For hue 7.5YR or yellower:

Moist color: value < 4 and chroma < 3.

Dry color: value < 6.

For hues redder than 7.5YR:

Moist color: black or very dark gray (Munsell).

Dry color: value < 5.

Spodic qualifier

This qualifier is used to describe soils with illuvial accumulation of organometallic complexes in the subsurface and that do not fulfill the criteria for a spodic B horizon and Espodossolos.

Eutric qualifier

This qualifier is used to distinguish soils with pH (in H₂O) ≥ 5.7, together with an S value (sum of bases) of ≥ 2.0 cmolc kg⁻¹ soil within the control section that defines the class.

Fluvic qualifier

This qualifier is used to identify soils formed under strong influence of alluvial or colluvial–alluvial sediments, which meet at least one of the following requirements:

Stratified layers, identified by irregular (erratic) variations in particle size or other soil attributes with increasing depth; and/or

Irregular (erratic) distribution of organic carbon with increasing depth, which is unrelated to the pedogenetic processes.

Lithoplinthic qualifier

This qualifier is used to define soils with continuous and consolidated petroplinthite in one or more horizons in some part of the control section that defines the class, with insufficient thickness of the ferruginous material for a classification as lithoplinthic horizon.

Planic qualifier

The planic qualifier is used to identify dense horizons with slow or very slow permeability, grayish or darkened, neutral or nearly neutral colors, or with reduced mottles, which do not meet the requirements for planic horizons and that occur along the entire length of the horizon, with exception of horizons with a plinthic qualifier. It also applies to soils with a redoxic qualifier above the B horizon and with an abrupt textural change.

Plinthic qualifier

This qualifier is used to differentiate soils that contain an insufficient quantity of plinthite or that have one or more horizons with a satisfactory quantity of plinthite, but which are not thick enough to characterize a plinthic horizon, in some part of the control section that defines the class. Plinthite must account for a minimum amount of 5% per volume.

Redoxic qualifier⁸

This qualifier refers to the presence of redoximorphic features (United States, 1999; Kämpf; Curi, 2012) in the control section that defines the class, resulting from temporary waterlogging of horizons and/or layers, leading to the occurrence of reduction and oxidation processes, with iron and/or manganese segregation, in the form of mottled and/or variegated colors. The redoxic qualifier does not apply to plinthic and gley horizons, and does not have precedence over the plinthic qualifier.

Temporary water saturation can occur in horizons located above a B horizon with low hydraulic conductivity, sometimes forming a suspended water-saturated zone. In this case, the redoxic qualifier can occur in areas closer to the soil surface, in horizons that precede the B horizon and/or on top of it. In other cases, temporary waterlogging can occur in deeper layers, favored by the existence of horizons or layers with very low permeability, e.g., in areas above dense layers (fragipan or duripan) and in poorly permeable saprolites or even rock.

In any case, the period of waterlogging must last long enough to form a temporarily reducing condition, which can promote the dissolution of iron and/or manganese compounds and subsequent segregation when drying.

The redoxic qualifier is expressed by variegated colors or at least common and distinct mottles; diffuse mottles are admitted, if the amount is abundant. The mottled color pattern can vary largely, depending on the intensity of the oxidative-reductive processes, texture, position of the soil in the landscape and others. Temporary waterlogging, promoting mainly a depletion of iron compounds, may induce from a strong bleaching of the soil matrix (in this case, restricted to the horizons above or at the top of the B horizon) to a more colorful matrix, interspersed with bleached depletion zones, generally forming reticulate or polygonal patterns similar to plinthite.

The definition of the redoxic qualifier includes the epiaquic, previously described in the SiBCS editions of 1999 and 2006. Its limits were expanded to include the occurrence of redoximorphic features, both in the surface horizons and in the subsurface horizons or layers. The redoxic qualifier should be applied to express temporary waterlogging in layers or horizons of the profile. These soils, in general, have moderate or imperfect drainage, distinguishing them from the classes that are typical. The occurrence of a redoxic qualifier down to 50 cm below the soil surface is identified as an epirredóxico soil class. When found at a depth below 50 cm and ≤ 150 cm below the soil surface, it is identified as an endorredóxico soil class.

This criterion was adapted from FAO (1998), United States (1999) and Kämpf and Curi (2012).

Retractable qualifier⁹

This qualifier is used for the Latossolos and Nitossolos classes, suborders Brunos and Vermelhos, with clayey and very fine clayey texture. In soils with this qualifier, a marked retraction of the profiles is observed after exposure to a drying effect for some weeks, resulting in the formation of deep vertical cracks and large and very large prismatic-like structures (Figure 21, Appendix K), which break up into blocks when handled. In road cuts, with greater exposure to sunlight, the blocks will naturally tend to be separated in increasingly smaller structural units that are detached from the soil mass and accumulated in the lower part of the profile, forming a triangular shape similar to a "skirt" when looking sideways at the vertical section of the profile (Figure 23, Appendix K). Although kaolinite is the predominant clay mineral in these soils, the retractable qualifier is possibly due to the presence of hydroxy-Al interlayered 2:1 clay minerals (vermiculite with hydroxy-Al and smectite with hydroxy-Al), interstratified kaolinite-smectite, and/or to the small size of the clay minerals in the clay fraction. This qualifier is typically found in some soils of the mountainous highlands of southern Brazil, in a humid tropical climate.

A methodology of quantitative evaluation of the retractable qualifier, currently being tested, was proposed by Silva et al. (2017).

Rubric qualifier

This qualifier is used to indicate reddening with increasing depth in the soil classes of Latossolos Brunos and Nitossolos Brunos. In some part of the control section that defines these classes (exclusive BC horizon), they have a moist color with hues redder than 5YR and value ≤ 4, and hues of the dry color only one unit higher.

Salic qualifier¹⁰

This qualifier indicates the presence of salts more soluble in cold water than calcium sulfate (gypsum), and at levels that are toxic for most crops. It is indicated by the values of electrical conductivity in a saturated extract of ≥ 7 dS m⁻¹ (at 25 °C), at some time of the year.

Saline qualifier¹⁰

This qualifier indicates the presence of salts more soluble in cold water than calcium sulfate (gypsum), at levels that interfere with the development of most crops. It is indicated by the values of electrical conductivity in a saturated extract of ≥ 4 dS m⁻¹ and < 7 dS m⁻¹ (at 25 °C), at some time of the year.

This criterion was adapted from United States (1951, 1954).

Sodic qualifier

This qualifier discriminates horizons or layers with a sodium saturation (100 Na+ / T) ≥ 15% in some part of the control section that defines the class.

This criterion was adapted from United States (1954, 1999).

Solodic qualifier

This qualifier identifies horizons or layers with a sodium saturation (100 Na+ / T) varying from 6% to < 15% in some part of the control section that defines the class.

This criterion was adapted from IUSS Working Group WRB (1999).

Sombric qualifier¹¹ ¹²

This qualifier is observed in certain transitional or main subsurface horizons, (AB, BA, or B), of mineral soils with free drainage and low base saturation. These soils show evidence of humus accumulation, which does not fit in the definition of a spodic horizon nor fulfills the requirements for a buried A horizon. Soils with a sombric qualifier must meet all of the following criteria:

Must have a thickness of ≥ 10 cm;

Must not have an overlying eluvial E horizon;

Must not meet the set of characteristics required for a spodic horizon;

Have a lateral continuity of the dark subsurface horizon in the various landscape segments, indicating a pedogenic origin and thus discarding the possibility of being a buried A horizon;

Have hues and chromas, when dry and/or moist, lower than the colors of the overlying horizon;

Have a base saturation of < 50% (dystrophic); and

Have evidence of humus accumulation, be it by the presence of cutans preferably deposited on the ped surfaces or in the pores (rather than evenly distributed in the matrix), or be it by a higher carbon content than in the immediately overlying horizon.

Vertic qualifier

This qualifier identifies the presence of slickensides (friction surfaces), cracks or cuneiform and/or parallelepiped structures of insufficient quantity and expression to characterize a vertic horizon.

Lithic contact

This qualifier refers to the contact between the soil (any horizon or layer) and the underlying material that has a practically continuous mineral constitution and extreme resistance to breaking with a hammer. The resistance can be so high that, even when moist, digging with the shovel is virtually unfeasible or extremely difficult, and the free growth of the root system and water circulation are impaired and restricted to some random fractures and/or diaclases. These materials are represented by intact rocks (layer R) or with some degree of alteration from hard to extremely hard, of any nature (igneous, sedimentary or metamorphic), or by transitional or intermediate layers consisting mostly of hard rock (RCr or R/Cr). The interface between the soil and the petrocalcic, lithoplinthic, concretionary, ortstein, placic, fragipan and duripan diagnostic horizons is not considered a lithic contact.

Fragmentary lithic contact

The fragmentary lithic contact refers to a type of lithic contact in which the material underlying the soil, with the same nature and characteristics as a lithic contact, is fragmented instead of forming a continuous homogeneous layer or with only few occasional cracks, allowing root penetration and growth and water circulation.

Sulfidic materials

These materials contain oxidizable sulfur compounds that occur in mineral or organic soils in waterlogged areas, with pH values exceeding 3.5. If incubated in the form of 1 cm thick layers under moist aerobic conditions (field capacity) and at ambient temperature, the pH decreases 0.5 or more to values of ≤ 4.0 (1:1 by weight in water or with a minimum of water to allow the measurement), within a period of up to eight weeks.

Sulfidic materials are accumulated in soil or sediment, permanently saturated with brackish water. Sulfates in the water are biologically reduced to sulfides, to the extent that the materials are accumulated. Sulfidic materials are very often found in coastal wetlands and near the delta of rivers that carry non-calcareous sediments, but may occur in freshwater wetlands if the water contains sulfur. Sulfidic materials in high terrains may have been accumulated similarly in past geological periods.

If a soil containing sulfidic materials is drained or if the sulfidic materials are exposed in some other way to aerobic conditions, the sulfides oxidize and form sulfuric acid. The pH value, normally close to neutral prior to drainage or exposure, can drop to values < 3.0. The acid can induce the formation of iron and aluminum sulfates. The basic iron sulfate [K Fe (SO₄)₂ (OH)₆] (jarosite) can be segregated, forming the yellow mottles that usually characterize the sulfuric horizon. The transition from sulfidic materials to a sulfuric horizon normally takes few years but can also occur within a few weeks. Sulfidic material samples, air-dried in the shade for approximately two months and with occasional re-moistening, become extremely acid.

Although there is no specification of a color criterion of sulfidic materials, the materials of mineral soil qualified as sulfidic almost always have colors with chroma ≤ 1 or lower (neutral colors N). On the other hand, the sulfidic material of an organic soil usually has higher chromas (≥ 2). The values are ≤ 5, most often ≤ 4. The hues are 10YR or yellower, sometimes with greenish or bluish hues. Sulfidic materials generally have no mottles, except for different gray or black degrees, unless an oxidation process is setting in, which is evidenced by iron oxide precipitation in cracks or channels.

This criterion was derived from Fanning et al. (1993), United States (1994) and Kämpf et al. (1997).

Iron oxide content

Using the content of iron oxides (expressed in the form of Fe₂O₃ determined by sulfuric acid digestion) in the discrimination of the soil classes allows a clearer differentiation. Based on the iron oxide contents, the following classes can be separated:

Soils with low iron oxide content: contents < 80 g kg⁻¹ soil (hypoferric);

Soils with medium iron oxide content: contents from 80 g kg⁻¹ to < 180 g kg⁻¹ soil (mesoferric);

Soils with high iron oxide content: contents from 180 g kg⁻¹ to < 360 g kg⁻¹ soil (ferric). The term "ferric" is also applied to the class of Nitossolos for soils with Fe₂O₃ (H₂SO₄) contents of ≥ 150 g kg⁻¹ and < 360 g kg⁻¹ soil; and

Soils with very high iron oxide content: contents ≥ 360 g kg⁻¹ soil (hyperferric).

Andic properties

This property refers to the presence of amorphous inorganic compounds or with a low degree of structural arrangement, such as allophane and imogolite (silandic modalities), or resulting from the presence of humus-complexed Al and Fe (aluandic modalities).

Defining criteria:

Soil density ≤ 0.9 kg dm⁻³; and

Phosphate retention ≥ 85%; and

Alox + ½ Feox ≥ 2%.

The criteria are based on the WRB systems (IUSS Working Group WRB, 2015) and Soil Taxonomy (United States, 2014), as well as on the study of Santos Júnior (2017). They are still in the validation phase, recommended as differentiating criterion at the level of the 5th category, for the classes of Cambissolos Hísticos and Organossolos Fólicos.

Degree of decomposition of organic material

The following attributes are used for Organossolos:

Fibric organic material – organic material consisting of fibers¹³, easily identifiable as plant-derived material. It has a rubbed fiber content¹⁴ of ≥ 40% by volume and a pyrophosphate index of ≥ 5. If the fiber content is ≥ 75% by volume, the pyrophosphate criterion is not applicable. On the von Post decomposition scale, fibric material is usually grouped in the classes 1 to 4 (Appendix D). Its colors, determined by the sodium pyrophosphate method, assessed on the page of hue 10YR, have hue values and chromas of 7/1, 7/2, 8/1, 8/2 or 8/3 (Munsell..., 1994);

Hemic organic material – organic material in intermediate decomposition stage between fibric and sapric. The material is partially altered by physical and biochemical action. It does not meet the requirements for fibric or sapric material. The rubbed fiber content varies from 17% to 40% by volume. Hemic material is usually classified on the von Post decomposition scale in class 5 or 6 (Appendix D);

Sapric organic material – organic material in advanced decomposition stage. Normally, it has the lowest fiber content, the highest density and lowest water-holding capacity in the saturated state of the three types of organic materials. It is physically and chemically highly stable, changing very little over time, unless the soil is drained. The rubbed fiber content is less than 17% by volume, and the pyrophosphate index is ≤ 3. Sapric material is usually classified on the von Post decomposition scale in class 7 or higher (Appendix D). The colors, determined by the sodium pyrophosphate method, assessed on the page of hue 10YR, have values below 7, except for the value-chroma combinations of 5/1, 6/1, 6/2, 7/1, 7/2 or 7/3 (Munsell..., 1994).

This criterion was derived from United States (1998).

Other attributes

These attributes alone do not differentiate soil classes, but are important characteristics that support their definition.

Clay films

This property refers to the concentration of inorganic material in the form of pore filling, coating of structural units (aggregates or peds) or of coarse fraction particles (sand grains, for example) that have a glossy appearance and a waxy brightness. Clay films may be the result of coating by inorganic material, often clay, and/or the rearrangement of particles on the surfaces of the structural units (clay films, cutans etc). Once detected, this characteristic should be described in the field, according to Santos et al. (2015), and it can be confirmed by micromorphological analysis. Clay films include all occurrences of cutans and others in their different forms of expression.

In short, clay films consist of coatings with a glossy appearance and waxy sheen, similar to liquid melted wax, covering structural units or primary particles. In both cases, the property can be identified more easily with an at least 10-fold magnifying glass, by direct observation of the surface of the elements or of the edges of the sections resulting from the breaking of the peds.

As an attribute, clay films can be essential in the definition of textural and nitic B horizons and for the distinction between these and other diagnostic horizons.

This criterion was adapted from United States (1999).

Compression surfaces

These surfaces are smooth, virtually ungrooved, resulting from compression of the soil mass by the expansion of the material due to hydration, which can have a certain sheen when moist or wet.

Compression surfaces represent one of the most common features of soils with clayey or very fine clayey texture, and the inclination of the surfaces has no preferential orientation in relation to the perpendicular line of the profile. They are observed on the external part of the aggregates.

They are observed in two forms:

Shiny compression surfaces: surfaces with glossiness, according to the soil moisture level. They are observed on soils with a strong structural development, consisting of blocks or prisms, generally with good drainage, which may or may not be associated with the presence of coatings (clay films). They are frequent in, for example, Nitossolos Vermelhos; and

Dull compression surfaces: very fine and not very clear surfaces, usually with little color contrast with the aggregate matrix, with a blurry or dull appearance and that cannot be identified as clay films (Curi, 1993). They are frequent in, e.g., Nitossolos Brunos.

Note: not all dull surfaces are compression surfaces.

Gilgai

This is the typical microrelief of clayey soils with a high expansion coefficient under increasing moisture content.

It consists of convex projections distributed in almost flat areas or constitutes a topographical succession of small depressions and elevations.

This criterion was adopted from United States (1999).

Self-mulching

This property is inherent to some clay materials that form a surface layer of generally granular and loose aggregates, strongly developed, resulting from wetting and drying. When destroyed by the use of agricultural implements, the aggregates are normally restored by the effect of only one wetting-drying cycle.

This criterion was adopted from United States (1999).

Silt/clay ratio

This relation is calculated by dividing the silt by the clay contents, based on results of particle-size analysis. The silt/clay ratio can be used to assess the weathering degree of soils of tropical regions. The ratio is used in soils of sandy loam texture or finer. It indicates a high weathering degree when most part of the B horizon has a value of < 0.7 in loamy textured soils or < 0.6 in clayey or very fine clayey soils. This ratio can be used as additional characteristic to distinguish the incipient B from latosolic B horizons if the morphological characteristics are similar, and particularly to identify soils with parent material derived from crystalline rocks such as granitic and gneissic rocks.

Alterable minerals

In comparison with other more resistant minerals such as quartz and clays of the kaolinite group, these minerals are unstable, mainly in humid climate zones, and release plant nutrients and iron or aluminum under weathering. The minerals referred to as alterable are:

Minerals found in the fraction finer than 0.002 mm (clay fraction): includes all types of 2:1 clay minerals, except for hydroxy-Al interlayered vermiculite (HIV), commonly found in Latossolos and some Argissolos and Nitossolos;

Minerals found in the fraction between 0.002 and 2 mm (silt and sand fraction minerals): feldspars, feldspathoids, ferromagnesian minerals such as pyroxenes and amphiboles, volcanic glasses, zeolites, apatite, and micas, including muscovite (which is weathering-resistant for some time, but also tends to disappear eventually).

This criterion was derived from FAO (1990) and United States (1994).

Textural grouping

This grouping unites one or more texture classes (Figure 1). Recorded in simple binary or ternary notation, the following textural groupings are differentiated:

Sandy texture – material that comprises the sand and loamy sand textural classes , i.e., sand content minus clay content > 700 g kg⁻¹;

Loamy texture – material with < 350 g kg⁻¹ clay and > 150 g kg⁻¹ sand, aside from the textural classes sand and loamy sand;

Clayey texture – material with clay content between 350 g kg⁻¹ and 600 g kg⁻¹;

Very fine clayey texture – material with a clay content of > 600 g kg⁻¹;

Silty texture – material with < 350 g kg⁻¹ clay and < 150 g kg⁻¹ sand.

Figure 1. Guide to textural class grouping.

The textural contrasts between soil horizons are expressed in binary or ternary notation, in the form of fractions, e.g., loamy/clayey texture" (binary) and "sandy /loamy/very fine clayey texture" (ternary). The textural contrasts can be used in several soil classes to indicate variations in textural classes in deeper layers.

Gravel distribution in the profile

This property indicates the macroclastic constitution of the mineral soil component. It is a distinctive feature, depending on the proportion of gravel (from 2 mm to 2 cm) in relation to the fine earth fraction (< 2 mm). When the gravel quantity is high, it should be used as a modifier of textural grouping or subgrouping, in the following classes (Santos et al., 2015).

Slightly gravelly – gravel content between 80 g kg⁻¹ and < 150 g kg⁻¹;

Gravelly – gravel content between 150 g kg⁻¹ and 500 g kg⁻¹;

Very gravelly – gravel content > 500 g kg⁻¹.

The occurrence of gravel is used as qualifier in the textural grouping or subgrouping, as for example in: "gravelly clayey texture".

Skeletal soil constitution

This constitution refers to soils with more than 35% and less than 90% of the total volume of the soil mass consisting of mineral material with a diameter of > 2 cm. The property qualifies the textural grouping or subgrouping (e.g., "skeletal sandy texture" or "sand skeletal texture"). When more than 90% of the volume below the surface of a soil fulfills this condition of mineral material, it is considered a type of terrain.

Notes

(4) Determined based on the sum of exchangeable bases (Ca2+ + Mg2+ + Na+ + K⁺) and extractable acidity (H+ + Al³⁺), according to Claessen (1997), Donagemma et al. (2011) and Teixeira et al. (2017). This procedure results in other values than those established by the analytical methodology used by the Natural Resources Conservation Service (formerly Soil Conservation Service), of the United States Department of Agriculture (USDA).

(5) Calculated according to the methodology used by Embrapa Soils (see Appendix D).

(6) Some examples of soils with chromic and non-chromic qualifier: Luvissolos: Bruno Não Cálcico (chromic) – profile 26 (Jacomine et al., 1971, p. 241); Podzólico Bruno-Acinzentado (non-chromic) – profile 5 (Embrapa, 1980a).

(7) Examples of soils with ebanic and non-ebanic qualifier: Chernossolos: dark colored (ebanic) – profile 5 (Embrapa, 1980b); less dark colored (non-ebanic) – profile 70 (Larach et al., 1984).

(8) In the validation phase.

(9) In the validation phase.

(10) It should be emphasized that the electrical conductivity alone is insufficient to determine the presence or absence of saline and salic qualifiers; the soluble salt contents should be analyzed, since values of 4.0 dS m⁻¹ and 3.5 dS m⁻¹ can be found in the sulfuric horizon, as observed in certain soils of the Usina Coruripe, in Alagoas.

(11) In the validation phase.

(12) From the French word sombre, which means "dark".

(13) "Fiber" is defined as organic material containing evidence of plant remains, exclusive of live parts, retained on a 100 mesh (0.149 mm). Woody fragments that cannot be squeezed between the fingers and are > 2 cm in the smallest dimension are excepted.

(14) "Rubbed fiber" refers to the fiber retained in a 100 mesh screen after rubbing a sample of organic material between thumb and forefinger for about 10 times.

Chapter 2

Diagnostic surface horizons and diagnostic subsurface horizons

Diagnostic surface horizons

Histic horizon

Histic horizons have characteristics mainly related to the high organic matter content, with black, very dark gray or brownish colors. They are the result of the accumulation of plant residues, in varying degrees of decomposition, deposited on the soil surface, although at present they may be covered by mineral horizons or deposits, and even by younger organic layers. Even after disturbance of the soil surface (for example by plowing), the levels of organic carbon (Valladares, 2003), after mixing with mineral material derived from inferior horizons or layers, are still high and ≥ 80 g kg⁻¹.

The histic horizon is formed in two distinct environments:

Histic O horizon – formed from material deposited under free drainage conditions (water-saturated for less than 30 consecutive days during the rainy season), without water stagnation, primarily conditioned by wet and cold climate and high-mountain vegetation. It can be found on top of a lithic contact, fragmentary lithic contact or any type of horizon (A, B or C);

Histic H horizon – formed from materials deposited under waterlogged conditions, for several months or all year long, although at present, it may have been artificially drained. These horizons are generally found overlying the C horizon, and in some cases, due to the influence of artificial drainage, over the A and B horizons. They can occur at the surface or be buried by mineral material.

A histic horizon must meet one of the following requirements:

A thickness of ≥ 20 cm;

A thickness of ≥ 40 cm, when 75% or more of the volume of the horizon consists of plant tissue in the form of residues of fine branches, fine roots and tree barks, excluding live roots;

A thickness of ≥ 10 cm when overlying a lithic or fragmentary lithic contact or a horizon and/or layer consisting of 90% or more (by volume) of mineral material, with a diameter of ≥ 2 mm (gravel, pebbles and boulders).

Chernozemic A horizon

Chernozemic A horizons are surface mineral horizons, relatively thick, dark colored, with high base saturation and which, even after superficial soil disturbance (for example by plowing), must have the following characteristics:

A well-developed soil structure, with aggregation and degree of development predominantly moderate or strong, ruling out a simultaneously massive structure and a hard, very hard or extremely hard consistence when dry. Prisms without secondary structure, > 30 cm, are not admissible either, nor a massive structure;

Chroma of the moist soil color ≤ 3, and values equal to or darker than 3 when moist and equal to or darker than 5 when dry. If the surface horizon contains 400 g kg⁻¹ soil or more of calcium carbonate equivalent, the limits of the value are disregarded when dry; when moist, the limit is ≤ 5;

Base saturation (V) of ≥ 65%, with predominance of calcium and/or magnesium ions;

Organic carbon content of ≥ 6 g kg⁻¹ soil throughout the horizon, according to the thickness criterion in the next item. If, due to the presence of 400 g kg⁻¹ soil or more of calcium carbonate equivalent, the color requirements depart from the usual, the organic carbon content will be ≥ 25 g kg⁻¹ soil within the top 18 cm of the soil surface. The upper limit of the organic carbon content that characterizes the chernozemic A horizon is the lower limit of the histic horizon;

Thickness, including transitional horizons (such as AB, AE or AC), even when the soil material is overturned, according to one of the following requirements:

≥ 10 cm, if the A horizon is followed by contact with the rock; or

≥ 18 cm and more than one-third of the solum thickness (A+B), if less than 75 cm thick; or

For soils without a B horizon, ≥ 18 cm and over one-third of the thickness of the A+C horizons, if less than 75 cm thick; or

25 cm (minimum), if the solum has a thickness of ≥ 75 cm.

Humic A horizon

Humic A horizons are mineral surface horizons, with value and chroma (moist soil color) of ≤ 4 and base saturation (V) of < 65%, with thickness and organic carbon contents (OC) within specific limits, according to the following criteria:

Minimum thickness as described for the chernozemic A horizon;

Organic carbon content below the lower threshold of a histic horizon;

Total carbon content equal to or higher than the value calculated by the following inequation:

Σ (OC, in g kg⁻¹, of the A subhorizons x thickness of the subhorizon, in dm) ≥ 60 + (0.1 x weighted average of clay content, in g kg⁻¹, of the surface horizon, including AB or AC)15.

Thus, the following calculations should be used to evaluate whether the horizon qualifies as humic. Initially, the organic carbon content (g kg⁻¹) of each subhorizon is multiplied by the thickness of the same subhorizon, in dm [OC (g kg⁻¹) of each A subhorizon x thickness of the same subhorizon (dm)]. The sum of the products of the organic carbon contents by the thickness of the subhorizons is the total organic carbon (total OC) of the A horizon. Then the weighted average of clay of the A horizon is calculated, by multiplying the clay content (g kg⁻¹) of the subhorizon by the thickness of the same subhorizon (dm) and dividing the result by the total thickness of the A horizon, in dm (clay content of the A subhorizons in g kg⁻¹ x thickness of the same subhorizons in dm / total thickness of the A horizon in dm).

The total OC required to qualify a horizon as humic must be equal to or greater than the results of the following inequation:

Total OC ≥ 60 + (0.1 x weighted average of clay of the A horizon)

To facilitate the understanding of the above procedures, a practical example of the calculations performed in an A horizon, described and sampled in the field, is shown in Table 1.

(To see the table as an image, click here).

Table 1. Example of calculations for an A horizon.

Sub-
horizon

Depth
(cm)

OC

Clay

Calculation of the
weighted average of clay

Calculation of total OC

(g kg⁻¹)

A1

0-31

20.6

200

200 g kg⁻¹ x 3.1 dm/6.8 dm = 91.18 g kg⁻¹

20.6 g kg⁻¹ x 3.1 dm = 63.86 g dm kg⁻¹

A2

31-53

10.6

230

230 g kg⁻¹ x 2.2 dm/6.8 dm = 74.41 g kg⁻¹

10.6 g kg⁻¹ x 2.2 dm = 23.32 g dm kg⁻¹

AB

53-68

8.4

250

250 g kg⁻¹ x 1.5 dm/6.8 dm = 55.15 g kg⁻¹

8.4 g kg⁻¹ x 1.5 dm = 12.60 g dm kg⁻¹

Total = 220.74 g kg⁻¹

Total = 99.78 g dm kg⁻¹

Replacing the weighted average of clay in the inequation "total OC ≥ 60 + (0.1 x weighted average of clay)", we have:

Total OC ≥ 60 + (0.1 x 220.74) = 82.07

The value of total OC contained in the A horizon is 99.78, and therefore higher than 82.07 (the minimum to classify the horizon as humic) in function of the weighted average clay content of 220.74 g kg⁻¹. Thus, the horizon used as example is humic.

This criterion is as proposed by Carvalho et al. (2003).

Prominent A horizon

The characteristics of the prominent A are comparable to those of the chernozemic A horizon with regard to color, organic carbon content, consistence, structure and thickness, differing mainly in a base saturation (V) of < 65%. They differ from a humic A horizon in the organic carbon content coupled with thickness and clay content.

Anthropic A horizon

Anthropic A horizons are formed or modified by prolonged human use, either as area of residence, waste disposal or cultivation, where signs of addition of organic material of varied nature, mixed or not with mineral material are observed, based on evidence such as the presence of ceramic and/or lithic artifacts, bones, shells or traces of fire (charcoal and ash).

Aside from the obligatory presence of one or more of the above evidences of past human activity, an anthropic A horizon must meet the following requirements, in at least one of the A subhorizons (including intermediary horizons AB, AC and AE)¹⁶:

Thickness of ≥ 20 cm; and

Content of extractable P (in Mehlich-1 solution, Appendix D) ≥ 30 mg kg⁻¹ soil.

Weak A horizon

Weak A horizons are surface mineral horizons that are weakly developed, be it due to the reduced content of mineral or organic colloids, or to the external climate and vegetation conditions, as those in the semi-arid zone with xerophytic caatinga (deciduous thorny scrubland) vegetation.

The weak A horizon is identified by the following characteristics:

Soil color with value ≥ 4 when moist and ≥ 6 when dry; simple grain structure, massive or with a low development degree; and organic carbon content of < 6 g kg⁻¹; or

Thickness of < 5 cm, regardless of the conditions of color, structure and organic carbon content (any surface horizon with a thickness of < 5 cm is weak).

Moderate A horizon

This category includes the horizons that do not fulfill the set of criteria of the other diagnostic surface horizons.

In general, the moderate A horizon differs from the chernozemic, prominent and humic A horizons in thickness and/or color and from the weak A horizon in organic carbon content and structure, and does not meet the requirements of a histic or anthropic A horizon.

Diagnostic subsurface horizons

Textural B horizon

Textural B horizons are mineral subsurface horizons that have a sandy loam or finer texture, in which the clay increased (fraction < 0.002 mm), oriented or not, provided that not exclusively by discontinuity of the parent material. They result from the accumulation or absolute or relative concentration due to illuviation and/or in situ formation processes, and/or are inherited from the parent material, and/or infiltration of clay or clay plus silt, with or without organic matter, and/or clay destruction in the A horizon, and/or clay loss in the A horizon by differentiated erosion. The clay content of the textural B horizon is higher than that of the A or E and may or may not be greater than that of the C horizon.

This horizon can be found at the surface if the soil was partially truncated by erosion.

The colloidal nature of clay makes it susceptible to mobility in soil water in case of relevant percolation. Upon deposition in aqueous medium, the clay mineral particles, usually in laminar shape, tend to settle flat on the underlying surface. Transported by water, the translocated clays tend to form films, oriented in parallel to the surfaces they cover, in contrast to the clays formed in situ, which have no ordered orientation. However, other types of inorganic colloidal coating material are also taken into account as characteristics of the textural B horizon and recognized as clay films.

The clay films considered in the identification of the textural B horizon consist of colloidal mineral coating materials which, if well-developed, are easily identifiable by their shiny and glossy appearance, in the form of pore filling and coatings of the structural units (aggregates or peds).

In the soils without macroaggregates, with a simple grain or massive structure, illuvial clay occurs in the form of coating of individual sand grains, oriented according to the surface or forming bridges linking the grains.

For the field identification of most textural B horizons, clay films are important. However, the mere occurrence of clay films would be insufficient to characterize a textural B horizon, and a combination with other auxiliary criteria is required, since the pores can be filled in a single rainfall or flood event by turbulent water flow through cracks. For this reason, the clay films of a textural B horizon must be found on different surfaces of the structural units and not exclusively on the vertical surfaces.

A textural B horizon is recognized by the occurrence of lamellae with a sandy loam or finer texture, which together have a total thickness of 15 cm, and may contain material with sand and loamy sand texture in-between them.

In summary, the textural B horizon is formed under a horizon or surface horizons, and has a thickness that meets one of the following requirements:

Has at least 10% of the sum of the thicknesses of the overlying horizons and at least 7.5 cm; or

Has ≥ 15 cm if the A and B horizons together are thicker than 150 cm; or

Has ≥ 15 cm if the texture of the E or A horizon is loamy sand or sand; or

If the B horizon consists entirely of lamellae, these together must have a thickness of > 15 cm; or

Has a thickness of at least 7.5 cm, if the previous conditions (Items a through d) are not met.

In addition to the above, for the characterization of a textural B horizon, one or more of the following requirements must be fulfilled:

Presence of an E horizon in the sequum, above the respective B horizon, provided that the B does not meet the requirements for a spodic, plinthic or planic B horizon;

A large increase in total clay from the A to the B horizon, enough to characterize an abrupt textural change¹⁷; or

Increase in total clay from the A to B horizon, within a control section defined in function of the thickness of the A horizon, so that the textural B/A ratio¹⁸ satisfies one of the following alternatives:

In the soils with clay contents in the A horizon of > 400 g kg⁻¹, a ratio of > 1.50; or

In the soils with clay contents in the A horizon between 150 g kg⁻¹ and 400 g kg⁻¹, a ratio of > 1.70; or

In the soils with clay contents in the A horizon of < 150 g kg⁻¹, a ratio of > 1.80.

If the total clay increase from the A to B horizon is less than specified in item (h), the textural B horizon must satisfy one of the following conditions:

Soils with a loamy texture B horizon and without macroaggregates must contain illuvial clay, represented by moderate clay films in the form of coatings of individual sand grains, oriented according to their surface or forming bridges between them.

Soils with a loamy texture B horizon and a prismatic and/or moderate or strong blocky structure must have at least moderate clay films in one or more subhorizons of the upper part of the B.

Soils with a B horizon with a clayey or very fine clayey texture and a prismatic and/or moderate or strong blocky structure must have at least common and weak or low and moderate clay films (not admitting, however, few and weak clay films) in one or more subhorizons of the upper part of the B.

Soils with a textural B/A ratio ≥ 1.4, coupled with fragipan occurrence within 200 cm from the surface, provided the requirements for a spodic B horizon are not fulfilled.

If the profile has a discontinuity in the parent material between the A or E and the textural B horizons, provided that not exclusively (mainly soils developed from young materials, e.g., alluvial sediments) or if only a plowed layer lies above the textural B, it must satisfy one of the requirements specified in the items (h) and/or (i).

This criterion was derived from the argillic horizon, described in United States (1975, 1999).

Notes:
The textural B and nitic B horizons are not mutually exclusive. The distinction between Argissolos and Nitossolos is based on the clay contents, the textural gradient, occurrence of clay films and on the color variation in depth in the soil profile (polychromy), according to the criteria defining Nitossolos.

The identification and evaluation of the textural gradient in soils with an anthropic A horizon for taxonomic purposes is in the study phase. Initially, it was proposed that other criteria, apart from the textural gradient, must be met for the identification of the B horizon in these soils. The profile RO-08 of Rondônia, analyzed at the technical scientific event called Brazilian Meeting of Soil Classification and Correlation (RCC) (Reunião..., 2017) is an example.

Latosolic B horizon

Latosolic B horizons are mineral subsurface horizons in which the constituents are in an advanced stage of weathering, evidenced by the almost complete transformation of the easily alterable minerals, followed by intense desilicification, base leaching and residual concentration of sesquioxides and/or of 1:1 clay minerals and weathering-resistant minerals. In general, the latosolic B horizon consists of varying amounts of iron and aluminum oxides and 1:1 clay minerals, quartz and other more weathering-resistant minerals.

The latosolic B horizon should not contain more than 4% of the alterable primary minerals (low resistance to weathering) or 6% in the case of muscovite, determined in the sand fraction in relation to the fine earth fraction. The fraction of < 0.05 mm (silt + clay) may contain small quantities of interstratified clay or ilite, but not more than traces of clay minerals of the smectite group. The original rock structure, such as fine stratifications, saprolite or fragments of rocks with low resistance to weathering, should not account for more than 5% of the volume of the mass of the latosolic B horizon.

The latosolic B horizon must have a minimum thickness of 50 cm, a sandy loam or finer texture and low silt levels. In general, the silt/clay ratio is < 0.7 in loamy textured soils and < 0.6 in clayey or very fine clayey soils in most B subhorizons (exclusive BC) to a depth of 200 cm (or 300 cm if the A horizon has a thickness of > 150 cm). The silt/clay ratio requirement may not be met if the soil is derived from sediments or materials in which the high silt content does not reflect the presence of weatherable primary minerals.

The latosolic B horizon may have at most few and weak clay films. It may contain more clay than the overlying horizon, but the increment in the clay fraction with increasing depth is small, so that comparisons at intervals of ≤ 30 cm between the A and B horizons, or within the control section to calculate the textural relationship, indicate lower values than required to characterize a textural B horizon.

In some latosolic B horizons, the pH values determined in KCl 1 mol L⁻¹ solution are higher than those determined in H₂O, evidencing net positive charges, a characteristic indicating a highly advanced weathering stage.

The cation exchange capacity in the latosolic B horizon must be < 17 cmolc kg⁻¹ clay, without correction for carbon.

The molecular ratio SiO₂/Al₂O₃ (Ki) in the latosolic B horizon is < 2.2, and usually < 2.0.

The subhorizons of the latosolic B horizon are not very clearly differentiated, with generally diffuse transition.

In some cases, the field identification of the upper limit of the latosolic B horizon is difficult, since the transition contrasts little with the preceding horizon, and a clear contrast is almost only observed in color and structure, between the lower part of the A horizon and the latosolic B horizon.

The structure of this horizon can be strongly developed when the structural elements are granular, with very small and small sizes, or weak, and more rarely moderately developed, in the case of a subangular blocky structure. The consistence of the material of the B horizon varies from soft to very hard when dry and from firm to very friable when moist.

For a latosolic B horizon with a retractable qualifier, variations in structure and consistence (criteria still in the validation phase) are admitted¹⁹.

Usually, the latosolic B horizon has a high flocculation degree in the subhorizons furthest away from the surface and a lower organic matter content, evidencing the low clay mobility and high resistance to dispersion. In many loamy textured soils, particularly in those with lower clay contents and high weathering degree, with a balance of positive charges, the flocculation degree may not be high.

In summary, the latosolic B horizon is a subsurface horizon that has no diagnostic characteristics of gley, textural B, nitic B and plinthic horizons, can occur under any surface diagnostic horizon (except the histic) and must meet all of the following characteristics:

Weak, moderate or strong structure, very small or small granular, or in weak or moderate degree subangular blocks;

Minimum thickness of 50 cm;

Less than 5% of the volume with evident original rock structure, e.g., fine stratifications, saprolite or partially weathered or unweathered rock fragments;

Sandy loam or finer texture;

Molecular ratio SiO₂/Al₂O₃ (Ki)²⁰ ≤ 2.2, but usually < 2.0;

Less than 4% alterable primary minerals (less weathering-resistant) or less than 6% of muscovite in the sand fraction, but based on the fine earth fraction, and no more than traces of the smectite clay mineral group and only small quantities of ilites or interstratified clay minerals, in the fraction of < 0.05 mm (silt + clay);

Cation exchange capacity of < 17 cmolc kg⁻¹ clay, without correction for carbon;

Clay films, if any, at most poor and weak.

This criterion corresponds, in part, to the oxic horizon (United States, 1975, 1999).

Incipient B horizon

Incipient B horizons are subsurface horizons, underlying the A, Ap or AB, with a less advanced degree of physical and chemical alteration, but sufficient for the development of color or structural units, and in which more than half the volume of all subhorizons should not consist of the original rock structure.

An incipient B horizon must be at least 10 cm thick and meet all of the following characteristics:

Not satisfy the requirements established to characterize a textural B horizon, nitic B, spodic B, planic B and latosolic B, apart from not having cementation, hardening (duripan and petrocalcic horizon) or brittle consistence when moist (fragipan); in addition, have an insufficient amount of plinthite for a plinthic horizon and no marked evidence of the distinctive reduction of a gley horizon;

Have prevailingly brownish, yellowish and reddish colors, with or without mottles or grayish colors with mottles, resulting from the segregation of iron oxides;

Have a sandy loam or finer texture;

Have developed structural units in the soil (aggregates or peds) and absence of the original rock structure, in ≥ 50% of its volume; and

One or more of the following conditions indicating the pedogenetic development:

Higher clay content or higher chromas or redder hues than in the underlying horizon; clay content lower, equal to, or slightly higher than in the A horizon (in the latter case, not satisfying the requirements of a textural B horizon);

Removal of carbonates, reflected particularly by lower carbonate contents in relation to the underlying horizon with carbonate accumulation, or by the absence of lime-coated fragments (if the underlying accumulation horizon contains lime-coated fragments only in the basal part) or by the presence of some partially uncoated fragments, if all coarse fragments of the underlying horizon are completely coated with carbonate.

The morphological characteristics of the incipient B horizon may be similar to those of a latosolic B horizon, differing from the latter by meeting one or more of the following requirements:

Cation exchange capacity, without correction for carbon, of ≥ 17 cmolc kg⁻¹ clay;

≥ 4% alterable primary minerals (less weathering-resistant) or ≥ 6% muscovite, determined in the sand fraction, but based on the fine earth fraction;

Molecular ratio SiO₂/Al₂O₃ (Ki)21 > 2.2;

Thickness of < 50 cm; and

Original rock structure in ≥ 5% the volume of the horizon, with for example fine stratifications, saprolite or partially weathered or unweathered rock fragments.

When a same horizon meets, coincidently, the requirements of an incipient B and a vertic B horizon, diagnostic precedence for taxonomic purposes will be given to the vertic B horizon.

In the case of many soils below the diagnostic textural B, spodic B, latosolic B horizon, or a plinthic or gley horizon that coincides with the B horizon, there may be a transition horizon to the C, in which weathering and comparable alterations to those of the incipient B horizon are observed, although the aforementioned transitional horizon is not considered an incipient B horizon, due to its position below a horizon with a higher degree of pedogenic development.

This criterion corresponds, in part, to the cambic horizon, as in United States (1999, 2014).

Nitic B horizon

Nitic B horizons are mineral subsurface horizons, not hydromorphic, with a clay or very fine clayey texture, without or with a small clay increase from the surface to the subsurface horizon, expressed in a textural B/A ratio of invariably ≤ 1.5. The clay activity can be low or high, as long as it is combined with an aluminic qualifier.

The structure, with a moderate or strong development degree, is subangular and/or angular blocky or prismatic and, in this case, usually composed of blocks. The amount and development degree of the clay films are at least common and moderate. The nitic B horizon has a gradual or diffuse transition between its subhorizons and can be found at the surface if the soil was eroded.

To be identified as a nitic B horizon, the following requirements must be met:

Thickness of ≥ 30 cm, unless the soil has a lithic or fragmentary lithic contact within the first 50 cm from the surface, in which case it must be ≥ 15 cm;

Clayey or very fine clayey texture;

Structure in prismatic blocks of moderate or strong development degree associated with clay films in an at least common quantity and with strong or moderate degree; and

Low or high clay activity, as long as combined with an aluminic qualifier.

Variations in structure, consistence and clay films are admissible for the nitic horizons with the retractable qualifier (criteria still in the validation phase), and the following requirements must be fulfilled:

The observed soil structure, if in subangular or angular blocks, has a moderate or strong development degree; if prismatic, it must have a moderate or strong degree, individualized in blocks, also with a moderate or strong development degree;

When moist, the soil consistence is at least firm and when dry, very hard or extremely hard; and

The occurrence of weak and few clay films and/or compression surfaces (dull and/or shiny) is permitted.

Note: The textural B and nitic B horizons are not mutually exclusive. Nitossolos and Argissolos Vermelhos or Vermelho-Amarelos are distinguished from each other by clay contents, the textural gradient, occurrence of clay films and color variation in the deeper soil profile (polychromy), according to the criteria listed in the definition of Nitossolos.

Spodic B horizon

Spodic B horizons are subsurface mineral horizons, with a thickness of ≥ 2.5 cm (with exception of the placic horizon, with a thickness of ≥ 0.5 cm), with illuvial accumulation of humified organic matter combined with aluminum, which may or may not contain iron. Aluminum is always present in spodic horizons and must be essential for their formation.

They usually occur under any type of A horizon or under an E horizon (albic or not) that may be preceded by an A or histic horizon.

The spodic B horizon can occur at the surface if the soil was truncated or in case of a mixture of the surface soil layer due to agricultural use.

In general, the spodic B horizon has no defined structural organization, consisting of simple grain or massive structure types and possibly of others with a low development degree. In the spodic B horizon, sand and silt particles are commonly completely or partially coated with a thin film of illuvial material or the porous space is completely or almost completely filled with this material.

Based on the dominant illuvial compounds and the degree of cementation, the following types of spodic B horizon can be identified, which can be found separately or together in a soil profile:

Bs – usually with vivid, high chroma colors. The horizon is characterized by the accumulation (illuviation) of amorphous material, mainly of aluminum and iron combined with a low content of illuvial organic matter, except for discontinuous patterns in the transition between the A or E and the spodic B horizon. The colors are generally concentrated around hues 5YR, 7.5YR or 10YR, with value 4 or 5 (≤ 6) and chroma from 4 to 8.

Bhs – is identified by a significant accumulation of illuvial organic matter combined with aluminum and iron compounds, which may be distributed in bands or as mottles, agglomerates or striations, forming heterogeneous patterns in the horizon. The Bhs horizons contain significant quantities of oxalate-extractable iron and aluminum (Feo and Alo). However, the limits still need to be defined for Brazilian soils. In general, the horizons identified as Bhs have hues varying from 2.5YR to 10YR, and value/chroma of 3/4, 3/6, 4/3 or 4/4.

Bh – is characterized by the illuvial accumulation of organic matter-aluminum complexes, with little or no evidence of iron. The horizon is laterally relatively uniform. In horizons identified as Bh, dark colors prevail, with a value < 4 and chroma < 3.

Ortstein – the spodic B horizon may also occur in a consolidated form, called Ortstein (Bsm, Bhsm or Bhm). It has a minimum thickness of 2.5 cm, is continuous or almost continuous and strongly cemented, usually by organometallic complexes. The very firm or extremely firm consistence is generally independent of the soil moisture content.

Combinations of the above horizons can occur along the profile (e.g., Bh-Bhs, Bh-Bs or Bh-Bs-Bsm etc.), with variations in terms of transition, thickness, color patterns and other morphological attributes.

Placic²² – another horizon that can occur associated with or as a variation of the spodic B is the placic. It is a thin horizon with black to dark red color, apparently cemented by iron (or iron and manganese) and organic matter. It is rarely parallel to the soil surface. In general, it has a wavy shape and the direction changes within few centimeters.

Placic horizons form a barrier to water and the development of plant roots. There are few records of occurrence of this horizon and, consequently, of the variability of attributes, such as thickness and constitution. Based on the current knowledge, a placic horizon must meet the following requirements:

Be cemented or hardened by iron or iron and organic matter, accompanied or not by other cementing agents;

Be laterally continuous, except for vertical cracks spaced at least 10 cm apart, through which the root system can penetrate; and

Have a minimum thickness of 0.5 cm and a maximum of < 2.5 cm. When it is not associated to spodic horizons and Espodossolos (incipient B horizons of Cambissolos, for example), there is no requirement of maximum thickness.

Only the thickness differentiates the placic from the ortstein horizon. When present in an Espodossolo, its thickness is < 2.5 cm, whereas the thickness of ortstein is ≥ 2.5 cm.

In summary, the spodic B horizon has a variable minimum thickness, depending on its type, with illuvial accumulation of organometallic compounds, noting that aluminum is always present, may or may not include iron, and has one or more of the following characteristics:

An overlying E horizon (albic or not) and moist colors according to one of the following items:

Hue 5 YR or redder;

Hue 7.5YR, with a value of ≤ 5 and chroma ≤ 4;

Hue 10YR, with value and chroma ≤ 3;

Neutral colors, with value of ≤ 3 (N 3/).

One of the colors of the previous item or hue 7.5YR with a value of ≤ 5 and chroma 5 or 6, or hue 10YR with a value of ≤ 5 and chroma < 6 and with one or more of the following characteristics:

Cementation by organic matter and aluminum, with or without iron, in 50% or more of the horizon and firm or very firm consistence of the cemented parts;

In case of sandy or loamy texture, the sand grains have cracked coatings of organic matter and aluminum (that may or may not contain iron);

Percentage of aluminum plus half the percentage of iron (determined by ammonium oxalate) of ≥ 0.50; this value must be at least twice the proportion found in the overlying either A or E horizon.

Any color, if the horizon is continuously cemented by a combination of organic matter and aluminum with or without iron (ortstein), and has a very firm or extremely firm consistence when moist.

These criteria were derived from IUSS Working Group WRB (2015), Isbell (1996) and United States (1999).

Planic B horizon

Planic B horizons are special textural B horizons, with or without the sodic qualifier, underlying the A or E horizons, which have an abrupt textural change or abrupt transition associated with a textural relationship within the range specified for the textural B horizon (Chapter 2, subitem h), but calculated between the first B subhorizon and the immediately overlying horizon (A or E).

It has a prismatic structure, columnar or large or medium angular and subangular blocks, and sometimes a massive structure; with slow or very slow permeability and grayish or darkened colors and with or without neutral reduction colors or mottles. This horizon is usually dense and contains high levels of clay dispersed in water, which may be responsible for the formation of a suspended water-saturated zone, of temporary existence.

The colors of the planic horizon reflect its low permeability and must meet at least one of the following requirements:

Color of the hue (with or without mottles):

Hue 10YR or yellower, chromas ≤ 3 or exceptionally 4; or

Hues of 7.5YR or 5YR, chromas ≤ 2.

Variegated coloring with at least one color with hue and chroma as specified in item (a) (Jacomine et al., 1975a, p. 241, profile 45); or

Soils with hue 10YR or yellower, chromas ≥ 4, combined with mottles with chroma as specified in item (a) (Jacomine et al., 1975a, p. 312, profile 50).

For taxonomic purposes, the planic B horizon was given diagnostic precedence over the gley and textural B horizons and loses in precedence to the plinthic horizon, except for a planic B horizon in conjunction with the sodic qualifier.

Albic E horizon

Albic E horizons are commonly subsurface mineral horizons, in which the removal or segregation of mineral and organic colloidal material has progressed to the point at which the horizon color is determined mainly by the color of the primary sand and silt particles and not by their coating.

The albic E horizon must have a thickness of ≥ 1.0 cm and colors that meet one of the following requirements:

Value of the moist soil ≥ 6 and chroma in moist soil ≤ 3; or

Value of the dry soil ≥ 7 and chroma in moist soil ≤ 3; or

Value of the moist soil ≥ 4, value of the dry soil ≥ 5 and chroma in moist soil ≤ 2; or

Value of the moist soil ≥ 3, value of the dry soil ≥ 6 and chroma in moist soil ≤ 2.

Horizons whose color is due to finely divided limestone, which acts as a white pigment, are excluded from the albic E horizon, as well as sandy layers (C horizon) that satisfy the color criteria, but in which no pedogenetic process causing the removal of materials from the soil can be characterized.

The albic E horizon usually precedes a spodic B, textural B, planic B, plinthic horizon, gley horizon, fragipan or an impermeable layer that restricts water percolation. More rarely, it may appear at the surface due to soil truncation.

This criterion was derived from the albic horizon as decribed by FAO (1974) and United States (1994, 1999, 2014).

Plinthic horizon

Plinthic horizons are characterized by the presence of plinthite in quantities of ≥ 15% (by volume) and by a thickness of ≥ 15 cm.

They are mineral B and/or C horizons with a range of red and grayish or white colors, with or without yellowish or brownish colors, forming a reticulate, laminar or polygon pattern. The coloring is usually variegated, prevailingly reddish, yellowish brown, brownish yellow, grayish and whitish (less often light yellow). Many plinthic horizons have a grayish or whitish matrix, with abundant red, yellowish red and dark red mottles, and sometimes mottles with a yellowish shade.

The light colors, which may represent the horizon matrix, have hue and chroma as specified below:

Hues from 2,5Y to 5Y; or

Hues from 10YR to 7.5YR, with low chromas, usually ≤ 4, and ≤ 6 in the case of hue 10YR.

The reddish, brownish, yellowish or whitish colors, normally observed in the mottles of the horizon and in variegated coloring, have hue and chroma as specified below:

Hues from 10R to 7.5YR with high chromas, usually > 4; or

Hues 10YR, with very high chromas, typically > 6; or

Hues from 2.5Y to 5Y.

The texture is sandy loam or finer. The structure is variable, can be massive or in the form of weak or moderately developed blocks, also occurring in prismatic structures composed of blocks, mainly in soils with high activity clay. When dry, the plinthic horizon is generally compact, from hard to extremely hard; when moist, it is firm or very firm and may have extremely firm parts; when moist, the consistence varies from slightly plastic to very plastic and slightly sticky to very sticky.

The clay activity in the plinthic horizon is commonly low, with a molecular ratio Ki between 1.20 and 2.20. However, high activity clay was also observed in this horizon (Anjos et al., 1995).

The plinthic horizon is formed in terrain with a high water table or in which water percolation is at least temporarily restricted. Regions of hot and humid climate, with a plain to gently undulating relief, in low areas such as depressions, lowlands, base slopes and some resurgence zones favor the development of plinthic horizons, by allowing waterlogging of the soil for at least a part of the year and by exposure to fluctuations in the water table.

The presence of iron concretions and nodules immediately above the zone of the plinthic horizon can be a proof of plinthite in the profile, thus highlighting a marked influence of wetting and drying processes in these sections. This process is accelerated when the material is exposed in trenches, ditches or old road cuts.

When a same horizon satisfies simultaneously the requirements for a plinthic horizon and also for a textural B, latosolic B, nitic B, incipient B, planic B (excepting a planic B horizon with a sodic qualifier) or gley horizon, it will be identified as a plinthic horizon, which has taxonomic precedence over the former.

Concretionary horizon

Concretionary horizons are composed of ≥ 50%, by volume, of coarse material (with predominance of petroplinthite) consisting of iron or iron and aluminum nodules or concretions, in a soil matrix with varied texture or with coarse material. These horizons are identified as any of the following: Ac, Ec, Bc or Cc.

To be diagnostic, a concretionary horizon must be at least 30 cm thick.

When a single horizon meets, coincidently, the requirements for a concretionary horizon and of a textural B, latosolic B, nitic B, incipient B, planic (excepting planic B with a sodic qualifier), gley or any type of A horizon, the concretionary horizon will be given taxonomic precedence.

This criterion was derived from Carvalho et al. (1988), FAO (1990, 1994), IUSS Working Group WRB (2015) and Reunião... (1979a).

Lithoplinthic horizon

Lithoplinthic horizons are constituted by continuous or nearly continuous petroplinthite. This horizon can comprise a section of a highly fractured profile, but with predominance of petroplinthite blocks with a minimum size of 20 cm, or with few cracks, separated from each other by ≥ 10 cm.

To be diagnostic, a lithoplinthic horizon should have a thickness of ≥ 10 cm. This horizon is a major impediment to root penetration and free water flow.

The lithoplinthic horizon differs from a cemented spodic B horizon (ortstein) in that it contains little or no organic matter.

This criterion was derived from the lithoplinthic horizon, as proposed by Smith et al. (1977), Carvalho et al. (1988) and FAO (1994, 1998).

Gley horizon

Gley horizons are subsurface or sometimes surface mineral horizons, with a thickness of ≥ 15 cm. They are characterized by iron reduction and predominance of the reduced status, in the entire horizon or part of it, mainly due to stagnant water, as evidenced by neutral or close to neutral colors in the horizon matrix, with or without mottles with more vivid colors. This horizon is strongly influenced by the water table and a reducing moisture regime, virtually free of dissolved oxygen because of the year round or at least long-lasting waterlogging, associated with the oxygen demand due to biological activity.

This horizon can be composed of material of any textural class, with colors with rather low, close to neutral or actually neutral chroma, which however become more brownish or yellowish upon exposure of the material to air. In case of aggregation of the structure, the surfaces of the structural elements are grayish, bluish, greenish or neutral in the continuous phase and may have mottles with more vivid colors. The interior of the structural elements can have prominent contrasting mottles, but usually a network of lines or bands of low chroma surrounds the mottles. When there are no structural elements, the matrix of the horizon (background) typically has chroma ≤ 1, with or without mottles.

If the horizon is periodically water-saturated or the soil drained, some mottles should be present, with high chroma and yellowish or reddish colors resulting from iron segregation and oxide precipitation. Accumulations in the form of black or reddish black, soft or semi-consolidated mottles, or even of manganese, or iron and manganese nodules or concretions are possible.

When present, the plinthite content is < 15%.

The gley horizon may be a C, B, E or A horizon. It may or may not be coincident with an increased clay content in the soil, but a significant reduction must, in any case, be evident.

In summary, the gley is a mineral horizon, with a minimum thickness of 15 cm, with < 15% plinthite and is waterlogged by groundwater during some months or the whole year, unless it was artificially drained, with evidence of reduction processes, with or without iron segregation, characterized by one or more of the following requirements:

Dominance of colors of the moist soil, on the surfaces of the structural elements or in the matrix (background) of the horizon, if there are no structural elements, according to one of the following items:

Neutral colors (N 1/ N 8/) or bluer than 10Y; or

For hues redder than 5YR and values ≥ 4, the chromas must be ≤ 1; or

For hues 5 YR or yellower and values ≥ 4, the chromas must be ≤ 2, admitting, for soils with a dominant hue of 10YR or yellower, a chroma of 3, which should be lower in the underlying horizon; or

For all hues and any values, the chromas may be ≤ 2, as long as reduction mottles occur.

Variegated coloring with at least one of the colors according to one of the previous items; or

The presence of reduced iron indicated, in field tests, by the color developed after the application of chemical indicators, such as the dark blue color developed by potassium ferricyanide at 1% in aqueous solution or the intense red color developed by alpha, alpha-dipyridyl solution (Childs, 1981).

In any case, the neutral, greenish or bluish hues, or with chroma ≤ 3 are changed by drying²³ of the material upon exposure to air.

When a horizon concurrently meets the requirements for the identification as gley horizon and also as a diagnostic sulfuric, incipient B, textural B, nitic B or latosolic B horizon, it will be identified as gley horizon. In this case, the condition of gleization is considered decisive to identify the diagnostic horizon in relation to the other attributes that occur simultaneously in the horizon. In other cases of coincidence, the gley horizon will not have taxonomic precedence.

This criterion was derived from the G horizon, as proposed by United States (1951), and partly of the hydromorphic properties (FAO, 1974), gleyic properties (IUSS Working Group WRB, 2015) and cambic horizon (United States, 1975, 1999; IUSS Working Group WRB, 2015).

Calcic horizon

Calcic horizons are formed by the accumulation of calcium carbonate, normally in the C horizon, but can occur in the B or A horizon.

They have a thickness of ≥ 15 cm, are enriched with secondary calcium carbonate and contain ≥ 150 g kg⁻¹ calcium carbonate equivalent, with at least 50 g kg⁻¹ more carbonate than the underlying horizon or layer. This latter requirement is expressed in terms of volume, if the secondary carbonate of the calcic horizon occurs as gravel, concretions or in powder form. If the calcic horizon overlies marble, marl or other highly calcitic materials (≥ 400 g kg⁻¹ calcium carbonate equivalent), a decrease in the percentage of carbonate in depth is not required.

This criterion is as the calcic horizon proposed by United States (1975, 1999).

Petrocalcic horizon

Due to carbonate enrichment, calcic horizons tend to become progressively plugged with carbonates and cemented, forming a continuous, hardened and massive horizon, which is acknowledged as petrocalcic horizon. In the initial stages of the calcic horizon, carbonates of soft consistence are found disseminated in the soil matrix or accumulated in hardened concretions, or both. The petrocalcic horizon clearly shows the evolutionary advancement in the calcification process.

It is a continuous horizon, resulting from the consolidation and cementation of a calcic horizon by calcium carbonate or, in some places, by magnesium carbonate. There may be incidental presence of silica. The horizon is continuously cemented throughout the profile, to such an extent that dry fragments immersed in water do not fracture or break in pieces. When dry, it is impenetrable to a spade or auger drill. It has a massive or laminar structure, is very hard or extremely hard when dry and very firm or extremely firm when moist. The non-capillary pores are obstructed, and the horizon does not allow root penetration, except along vertical fractures, which are separated by 10 cm or more. The minimum thickness is > 10 cm, except in the case of a laminar horizon on consolidated rock, which is considered a petrocalcic horizon if it has a thickness of ≥ 1.0 cm.

This criterion is according to the petrocalcic horizon described by United States (1994).

Sulfuric horizon

Sulfuric horizons are ≥ 15 cm thick and composed of mineral or organic material that has a pH value measured in water (1:2.5; soil/water) of ≤ 3.5, indicating the presence of sulfuric acid. In addition, they must fulfill one or more of the following characteristics:

Jarosite concentration; or

Sulfidic materials immediately below the horizon; or

≥ 0.05% water-soluble sulfate.

The color of jarosite (which may have chroma ≥ 3) is not specified, and its presence is not necessarily required either. Sulfuric horizons without jarosite are found in materials with high organic matter content or in mineral materials deposited during a previous geological period and currently surface-exposed.

A sulfuric horizon is formed by the oxidation of sulfide-rich organic or mineral materials as a result of drainage, most commonly artificial.

The acidic conditions of this horizon are highly toxic to most plants. They can also be formed at mining sites where sulfidic materials were exposed as a result of surface mining, road construction, dredging or other earth movement operations.

This criterion was derived from the United States (1994, 1999, 2014) and Bissani et al. (1995).

Vertic horizon

Vertic horizons are subsurface mineral horizons, which, due to clay expansion and contraction, have typical pedological features consisting of: friction surfaces (slickensides) in at least common quantities, and/or cuneiform and/or parallelepiped structural units (Santos et al., 2015), whose longitudinal axis is inclined at ≥ 10° in relation to the horizontal plane, having at least 1 cm wide cracks in some of the drier periods of the year. Most frequently, the horizon texture varies from clayey to very fine clayey, and in the range of loamy texture, a minimum of 300 g kg⁻¹ clay is admitted. They are very hard or extremely hard when dry and plastic to very plastic and sticky to very sticky when moist. The vertic horizon may coincide with AC, B horizons (Bi or Bt) or C and be dark, grayish, yellowish or reddish. To be diagnostic, this horizon must have a thickness of ≥ 20 cm.

In irrigated or poorly drained areas (without noticeable cracks), the coefficient of linear extensibility (COLE) must be ≥ 0.06, or the linear extensibility should be ≥ 6 cm.

The vertic horizon has diagnostic precedence over the incipient B, nitic B and gley horizons.

Fragipan

Fragipans are subsurface mineral horizons, hardened when dry, continuous or present in ≥ 50% of the volume of another horizon, usually of loamy texture. It may be underlying a spodic B, textural B or albic horizon. The organic matter content is very low, the bulk density higher than that of the overlying horizons and fragipans are apparently cemented when dry, and therefore have a hard, very hard or extremely hard consistence.

When moist, the fragipan has weak to moderate brittleness, and the structural elements or fragments tend to break suddenly under pressure, rather than being slowly deformed. When immersed in water, a dry fragment becomes less resistant, may develop fractures with or without breaking off pieces, and slakes within a short period of time (approximately 2 hours).

The fragipan is usually mottled and the water permeability low or very low. When the texture is loamy or clayey, it normally has bleached zones (reduction environment) around polyhedrons or prisms, spaced at ≥ 10 cm in the horizontal dimension, forming a coarse polygonal pattern.

The fragipan obstructs or prevents root and water penetration into the horizon where it occurs.

This criterion was derived from the fragipan (United States, 1951, 1975, 1999, 2014).

Duripan

Duripans are subsurface mineral horizons, cemented, continuous or present in ≥ 50% of the volume of another horizon, with a variable degree of silica cementation and may also contain iron oxide and calcium carbonate. As a result, duripans vary in appearance, but all of them, when moist, have a very firm or extremely firm consistence and are always brittle, even after prolonged wetting.

In this horizon:

Cementation is so strong that dry fragments will not slake, even during prolonged wetting periods;

Silica coatings, present in some pores and in some structural surfaces, are insoluble in 1 mol L⁻¹ HCl solution, even during prolonged soaking, but are soluble in concentrated and heated KOH solution or in alternating acid and alkali treatments;

The cementation is not destroyed in over half of any laminar capping that may be present or in some other continuous or imbricate horizon, when the soil material is saturated with acid, but it is completely destroyed by heated and concentrated KOH solution, in a single treatment or alternated with acid;

The roots and percolating water do not penetrate into the cemented part, except along vertical fractures separated by a distance of ≥ 10 cm.

This criterion corresponds in part to the concept of indurated pans, as described by United States (1951, 1994).

Notes

(15) For soils that have only one surface horizon, i.e., no subhorizons, the calculation is based on the multiplication of the carbon content by the thickness. A similar procedure should be followed to calculate the weighted average of clay.

(16) In the validation phase. Values based on Cordeiro et al. (2017).

(17) The increase in clay mentioned here should not be exclusively due to a lithological discontinuity.

(18) Calculated by dividing the arithmetic mean of the total clay content of the B horizon (excluding the BC) by the average total clay of A, as described in the items below:

a) If the A horizon is less than 15 cm thick, consider a maximum thickness of 30 cm from the top of the B horizon (including BA) to compute the average clay in the B (excluding BC);

b) If the A horizon is 15 cm thick or more, consider a thickness, from the top of the B horizon (including BA), of twice the thickness of the A to compute the average clay in the B (excluding BC).

(19) The latosolic B horizon with a retractable qualifier must meet the following requirements:

a) The structure observed in the moist soil, if blocky, has a less than moderate development degree. Angular blocks, if any, are few, and the prismatic structure, if present, is weak;

b) The soil consistence, when moist, must not be firm, very firm or extremely firm and is very hard or extremely hard when dry.

(20) For soils with a clay content of < 200 g kg⁻¹, the molecular ratio SiO₂/Al₂O₃ (Ki) can be determined in the clay fraction.

(21) For soils with a clay content of < 200 g kg⁻¹, the molecular ratio SiO₂/Al₂O₃ (Ki) can be determined in the clay fraction.

(22) From the Greek word plax, "plane, level surface" (meaning a thin cemented horizon).

(23) Color modifications are commonly noticeable within a few minutes after exposing the moist clod to drying, breaking it open and comparing the color of the dry outer surface with the moist inner part.

Chapter 3

Categorical levels of the system
Nomenclature of classes
Bases and criteria
Concept and definition of the classes of the 1st categorical level (orders)

Categorical levels of the system

The categorical level of a soil classification system consists of a set of classes defined according to diagnostic attributes at the same level of generalization or abstraction and includes all of the soils that meet this definition. The characteristics used for the definition of a categorical level should be soil properties that can be identified in the field or deduced from other properties that are recognized in the field or based on knowledge of Soil Science and other related disciplines. The differential characteristics for the higher categorical levels of soil classification should be properties resulting directly from the processes of soil genesis or properties that affect soil genesis directly, because they have a greater number of accessory characteristics.

The Brazilian System of Soil Classification (SiBCS) defines six categorical levels: 1st categorical level (orders), 2nd categorical level (suborders), 3rd categorical level (great groups), 4th categorical level (subgroups), 5th categorical level (families) and the 6th categorical level (series). The concepts for the 6th level still need to be defined.

Classes of the 1st categorical level (orders)

In the case of the orders, in some classes of the SiBCS, soils that constituted individual classes in previous Brazilian soil surveys are now grouped together. This is the case of the Neossolos order, which includes the soils formerly called Regossolos, Solos Litólicos, Litossolos, Solos Aluviais and Areias Quartzosas.

The various classes of the 1st categorical level are separated by the presence or absence of certain attributes, diagnostic horizons or properties that can be identified in the field, indicating differences in the type and degree of development of processes that influenced soil formation. Thus, the separation of classes at the 1st categorical level was based on the signals left in the soil resulting from a set of processes that were considered dominant in its development. It is worth mentioning that the absence of these characteristics in the soil was also used as a criterion for the separation of classes at the 1st categorical level.

The diagnostic attributes that reflect the nature of the environment and the effects (signals) of the dominant formation processes of soil genesis should be the most relevant for the 1st categorical level, for having the highest number of accessory characteristics.

In the specific case of Organossolos, the purpose of the diagnostic attributes was the differentiation from soils consisting of mineral material. Thus, the properties to be used should contribute to:

Differentiate Organossolos from mineral soils;

Indicate the potential of modifications when drained and/or cultivated;

Predict or identify the quality of the mineral substrate and/or mineral residue;

Select differential characteristics that change little or very slowly due to land use and management, aside from allowing the prediction of the soil response and agricultural potential (differentials with a large number of accessory characteristics).

Classes of the 2nd categorical level (suborders)

These classes are separated by differential diagnostic attributes that:

Reflect the actions of other soil formation processes that occurred together with or affected dominant processes in soils whose diagnostic attributes had already been used to separate the soils at the 1st categorical level; or

Include those resulting from soil genesis, which are extremely relevant for plant development and/or non-agricultural uses, and which have a large number of accessory properties.

Classes of the 3rd categorical level (great groups)

These classes are separated by one or more of the following characteristics:

Type and arrangement of the horizons;

Activity of the clay fraction, sorption complex saturation by bases, aluminum or sodium and/or by the presence of soluble salts;

Occurrence of horizons or properties that limit root development and affect the free movement of water in the soil.

Classes of the 4th categorical level (subgroups)

These classes are separated according to the following concepts (adapted from the United States, 1999):

Typical – They are not necessarily the most common classes, nor representative of the central concept of the great group to which they belong. In some classes, typical subgroups simply represent the soils that do not meet the characteristics defined for the previous subgroups of the taxonomic key.

Intergrade or transitional to other orders, suborders or even great groups – The properties may be the result of processes that cause a given soil to develop from or in the direction of another soil class, or which has intermediate properties to other classes. Among the properties used to define subgroups as intermediate are: occurrence of other diagnostic horizons apart from those that define the class at the previous taxonomic level, overlying or underlying the main diagnostic horizon (e.g., vertissólicos, gleissólicos etc.); or diagnostic characteristics associated to another class with insufficient expression to define the diagnostic horizon (e.g., plintossólicos, tiônicos).

Extragrade – These subgroups have some properties that are not representative of the great group, but do not indicate a transition to another class (e.g., abrúpticos, antrópicos, lépticos).

The ordering of the classes of 4th categorical level was based on the degree of importance of the subgroup qualifier (listed in Table 1).

(To see the table as an image, click here).

Table 1. Ordering of classes of the 4th categorical level.

Classes

Classes

1 – fragmentários

25 – retráticos

2 – líticos

26 – vertissólicos

3 – leptofragmentários

27 – luvissólicos

4 – lépticos

28 – gleissólicos

5 – saprolíticos

29 – petroplínticos

6 – tiônicos

30 – plintossólicos

7 – carbonáticos

31 – espodossólicos

8 – sódicos

32 – planossólicos

9 – sálicos

33 – nitossólicos

10 – salinos

34 – argissólicos

11 – hipocarbonáticos

35 – latossólicos

12 – solódicos

36 – cambissólicos

13 – êutricos

37 – neofluvissólicos

14 – psamíticos

38 – organossólicos

15 – espessarênicos

39 – chernossólicos

16 – arênicos

40 – epirredóxicos

17 – êndicos

41 – endorredóxicos

18 – espessos

42 – rúbricos

19 – mésicos

43 – sômbricos

20 – térricos

44 – antrópicos

21 – abrúpticos

45 – espesso-húmicos

22 – dúricos

46 – húmicos

23 – plácicos

47 – típicos

24 – fragipânicos

The surveying person may combine subgroup qualifiers for the 4th level, not more than three of them, which must be ordered as indicated in Table 1. For example, Argissolo Vermelho Eutrófico solódico abrúptico plintossólico (see Chapter 5, Argissolo...).

Classes of the 5th categorical level (families)

The classes of the 5th categorical level of the SiBCS were subdivided based on morphological, physical, chemical and mineralogical characteristics and properties important for land use and management.

The recommended criteria should be tested in different soil classes, evaluating the adequacy of methodologies and responses in terms of agronomic and geotechnical relevance and for different purposes. This is a study subject that should be prioritized in research projects by the different institutions.

At this level, information of practical value is included, comprising differential characteristics to distinguish more homogeneous groups of soils.

Many qualifiers of the 5th categorical level are used for virtually all levels of soil surveys in the country (Rios, 2006) as, for example, types of the A horizon and textural groupings.

Classes of the 6th categorical level (series)

The 6th categorical level is being discussed and should be the most homogeneous of the system. It is the level that allows the most detailed interpretation of the soil surveys for various purposes.

The definition of classes at this level should be based on characteristics directly related to plant growth, mainly with regard to the development of the root system, the soil-water-plant relationships and important properties for interpretations for purposes of engineering, geotechnics and environmental planning.

Nomenclature of the classes

At the first categorical level (order), the names of the 13 classes are formed by the association of a formative element with the ending "-ssolos". In Table 2, the names of the classes are listed in alphabetical order, with the formative elements and meanings.

(To see the table as an image, click here).

Table 2. Formative elements and meaning of the names of the classes.

Classes

Formative Elements

Terms of connotation and remembrance

ARGISSOLO

ARGI

From Latin argilla, "clay"; connotative of soils formed under influence of clay accumulation

CAMBISSOLO

CAMBI

From Latin cambiare, "change", "exchange"; connotative of soils in formation (transformation). Incipient B horizon

CHERNOSSOLO

CHERNO

From Russian chorniy, "black"; connotative of soils rich in organic matter, with dark colors

ESPODOSSOLO

ESPODO

From Greek spodos, "plant ashes"; connotative of soils with an illuvial accumulation horizon of organic matter associated with the presence of aluminum. Spodic B horizon

GLEISSOLO

GLEI

From Russian gley, "mass of pasty soil"; connotative of excess water. Gley Horizon

LATOSSOLO

LATO

From Latin lat, "brick"; connotative of highly weathered soils. Latosolic B horizon

LUVISSOLO

LUVI

From Latin luere, "washing"; connotative of clay translocation. Textural B horizon with high base saturation and high activity clay (Ta)

NEOSSOLO

NEO

From Greek neo, "new"; connotative of soils with poor pedogenetic development

NITOSSOLO

NITO

From Latin nitidus, "brilliant"; connotative of shiny surfaces on the structural units. Nitic B horizon

ORGANOSSOLO

ORGANO

From Latin organicus, "proper of or belonging to carbon compounds"; connotative of soils with a strong or predominantly organic constitution. H or O horizon

PLANOSSOLO

PLANO

From Latin planus, "plain, flat"; connotative of soils developed on plains or in depressions with seasonal flooding. Planic B horizon

PLINTOSSOLO

PLINTO

From Greek plinthos, "tile"; connotative of colorful clay materials that harden when exposed to air. Plinthic horizon

VERTISSOLO

VERTI

From Latin vertere, "turn", "invert"; connotative of movement of soil material at the surface reaching the subsurface (expansion/contraction). Vertic Horizon

Classes of the 1st, 2nd, 3rd and 4th categorical levels

In morphological description sheets of soil profiles and in map legends, the classes of the 1st and 2nd categorical levels should be written entirely in capital letters; all words of the classes of the 3rd categorical level (great groups) start with capital letters; and the names of the 4th categorical level (subgroups) should be written entirely in lowercase letters, as shown in Table 3.

(To see the table as an image, click here).

Table 3. Nomenclature of soils in morphological description sheets and map legends.

NEOSSOLOS FLÚVICOS

Ta Eutróficos

Vertissólicos

1st and 2nd categorical levels

3rd categorical level

4th categorical level

The classes of the 3rd and 4th categorical levels should preferably end with the suffix "-ico" (see example in Table 3).

Classes of the 5th categorical level (families)

To ensure a certain degree of consistency in the nomenclature of the classes of the 5th categorical level, the following sequence of differential characteristics (separated by commas) is suggested to compose the denomination of the soil class: textural grouping; textural subgrouping; distribution of gravels, nodules and concretions in the profile; skeletal constitution of the soil; type of A horizon (as long as it was not used for other categorical levels); base saturation; aluminum saturation (alic); mineralogy; subgrouping of the activity of the clay fraction, iron oxide content and andic properties.

For the class of Organossolos, special criteria should be applied that focus on the nature of the soil organic matter.

At the 5th categorical level (family), the name of the soil is established by adding the relevant qualifiers to the subgroup name, in lowercase letters, separated by commas, as in the example: "Latossolo Amarelo Ácrico petroplíntico, gravelly clayey texture, endoconcretionary, moderate A, gibbsitic-oxidic, meso-ferric".

Classes of the 6th categorical level (series)

As the 6th categorical level is still being discussed, no nomenclature is proposed. However, some characteristics and properties are listed in Chapter 18), which may be used in the classification of soils at this level.

Translation into other languages and standardized wording of soil classes of the SiBCS in publications

Translations of the SiBCS content into other languages are allowed. However, the names of the soil classes should not be translated.

In continuous texts of books, magazine articles, theses, dissertations, tables and similar manuscripts, the classes of the 1st, 2nd and 3rd categorical levels should be written with an initial capital letter and the 4th categorical level spelled entirely with lowercase letters ("Neossolos Flúvicos Ta Eutróficos vertissólicos", for example).

On the other hand, the legends in the soil maps should be written as explained here in the taxonomic key, spelling the 1st and 2nd categorical levels with capital letters, the 3rd categorical level with an initial capital letter and the 4th categorical level with lowercase letters ("NEOSSOLOS FLÚVICOS Ta Eutróficos vertissólicos", for example).

Due to the similarity of names between taxonomic systems and for practical reasons, the names of the diagnostic horizons were translated from Portuguese into English. However, attention must be paid to the definitions, which diverge in relation to other taxonomic systems.

Bases and criteria

The bases²⁴ and criteria²⁵ underlying the conceptualization and definition of the current classes are:

Argissolos

Group of soils with a textural B horizon, with low activity clay or high activity clay, provided that combined with low base saturation or with an aluminic qualifier.

Basis – advanced development with incomplete ferralitization, along with a genesis characterized by kaolinite-oxide or virtually kaolinite, or vermiculite with Al-hydroxy interlayers and clay mobilization in the topsoil, with clay concentration or accumulation in the subsurface horizon.

Criterion – development (expression) of a diagnostic textural B horizon coupled with attributes that indicate the low activity or high activity of the clay fraction, provided that combined with low base saturation or with an aluminic qualifier.

Cambissolos

Group of soils, poorly developed, with an incipient B horizon.

Basis – incipient pedogenesis, as indicated by the development of the soil structure, with alteration of the parent material expressed by the almost complete absence of rock structure or sediment stratification, and colors with higher chroma, redder hues or higher clay content than in the underlying horizons.

Criterion – development of an incipient B horizon below a surface horizon of any type, possibly including a chernozemic A horizon, when low activity clay and/or low base saturation should be observed in the incipient B horizon.

Chernossolos

Group of soils with a chernozemic A horizon, with high activity clay and high base saturation, with or without accumulation of calcium carbonate.

Basis – not highly advanced development due to the strong influence of bissialitization maintaining basic divalent cations, especially calcium, resulting in a high saturation degree of the colloids and eventual calcium carbonate accumulation, promoting a near-neutral reaction with organic matter enrichment, favoring the complexation and flocculation of mineral and organic colloids.

Criterion – development of a diagnostic surface chernozemic A horizon, followed by the C horizon, provided that it is calcic, petrocalcic or carbonatic, or coupled with a textural B horizon or incipient B horizon, with or without a calcic horizon or carbonatic qualifier, always with high activity clay and high base saturation.

Espodossolos

Group of soils with a spodic B horizon.

Basis – influence of a podzolization process, with eluviation of materials consisting mainly of a mixture of humified organic matter and aluminum, which may contain iron or not, and consequent illuvial accumulation of these constituents.

Criterion – development of a diagnostic spodic B horizon below an E (albic or not), A or histic horizon.

Gleissolos

Group of soils with pronounced gleization.

Basis – hydromorphism expressed by strong gleization, resulting from processes of intense reduction of iron compounds, in the presence of organic matter, with or without alternation of oxidation, due to the fluctuation of the water table, under conditions of permanent or periodical excess of moisture.

Criterion – preponderance and depth of occurrence of attributes that indicate gleization associated with the identification of a gley horizon.

Latossolos

Group of soils with a latosolic B horizon.

Basis – highly advanced development with marked latosolization (ferralitization), resulting in intense weathering of the primary minerals and even of less resistant secondary mineral constituents, and a high relative concentration of resistant clay minerals and/or iron and aluminum oxides and hydroxides, with minimal clay mobilization or migration, ferrolysis, gleization or plinthization.

Criterion – development (expression) of a diagnostic latosolic B horizon, below any type of A horizon, and an almost absent or minor increase in clay content from A to B.

Luvissolos

Group of soils with textural B horizon, high activity of the clay fraction and high base saturation.

Basis – development under the influence of a bissialitization process together with iron oxide production and clay mobilization from the topsoil, with accumulations in the subsurface horizon.

Criterion – Development (expression) of a diagnostic textural B horizon with high activity of the clay fraction and high base saturation below an A or E horizon.

Neossolos

Group of poorly developed soils, without a defined diagnostic B horizon.

Basis – soil in the process of formation, either due to the weak action of pedogenetic processes, or to inherent properties of the parent material.

Criterion – insufficient expression of diagnostic attributes that characterize the various processes of formation, minimum differentiation of horizons, with individualization of A horizon followed by C or R, and predominance of characteristics inherited from the parent material.

Nitossolos

Group of soils with a nitic B horizon below the A horizon.

Basis – advanced pedogenetic development due to the action of ferralitization with intense hydrolysis, resulting in an oxidic-kaolinitic or virtually kaolinitic composition, or with the presence of hydroxy-Al interlayered 2:1 clay minerals (HIV and HIS).

Criterion – development (expression) of a nitic B horizon, below any kind of A horizon, with a small textural gradient, but structured in subangular or angular blocks or a prismatic structure, of moderate or strong degree, with marked clay films and/or a retractable qualifier.

Organossolos

Group of organic soils.

Basis – predominance of attributes of the organic constituents over those of the mineral constituents.

Criterion – development of a histic horizon under waterlogging, permanent or periodic, or water-saturated conditions for only a few days during the rainy period, such as in humid, cold environments and high-montane vegetation.

Planossolos

Group of mineral soils with a planic B horizon underlying any type of A horizon, which may or may not have an E horizon (albic or not).

Basis – intense clay removal from the topsoil and intense clay accumulation or concentration in the subsurface horizon.

Criterion – intense clay removal evidenced by clear differentiation between the planic B horizon and preceding A or E horizons, with an abrupt textural change or abrupt transition coupled with a marked texture difference between the A or E and the B horizon (Chapter 2, subitem h); restricted permeability of the subsurface, affecting water infiltration and the hydrological regime, with evidence of reduction processes, with or without iron segregation, as indicated by the color attributes, and mobilization and sorption of the cation Na⁺ may occur.

Plintossolos

Group of soils with strong plinthitization, with or without formation of petroplinthite.

Basis – localized iron segregation, acting as cementing agent, with marked consolidation.

Criterion – preponderance and intensity of occurrence of attributes that suggest plinthite formation, combined with a diagnostic plinthic, concretionary or lithoplinthic horizon.

Vertissolos

Group of soils with a vertic horizon.

Basis – restricted development due to the great capacity of movement of the soil material as a result of the phenomena of expansion and contraction, generally associated with high activity clays.

Criterion – expression and intensity of occurrence of attributes resulting from the phenomena of expansion and contraction of the clayey soil material.

Concept and definition of the classes of the 1st categorical level (orders)²⁶

Argissolos

Concept – soils consisting of mineral material, which are differentiated by the occurrence of a textural B horizon with low activity clay or with high activity clay, if combined with low base saturation or with an aluminic qualifier. The textural B horizon (Bt) is found immediately below any type of surface horizon, except the histic, although without fulfilling the requirements of the classes of Luvissolos, Planossolos, Plintossolos or Gleissolos.

Most soils of this class have a clear increase in the clay content from the surface horizon to the B horizon, with or without decrease in the underlying horizons. The transition between the A and Bt horizons is usually clear, abrupt or gradual.

Argissolos have variable depths, from strong to imperfect drainage, are reddish or yellowish and more rarely brownish or grayish. The texture varies from sandy to clayey in the A horizon and from loamy to very fine clayey in the Bt horizon, always with increasing clay content from the former to the latter.

They are moderately to strongly acidic, with high or low base saturation, predominantly kaolinitic and generally have a molecular ratio Ki between 1.0 and 3.3.

Definition – soils consisting of mineral material with low activity clay, or high activity clay when combined with low base saturation or with an aluminic qualifier and textural B horizon immediately below the A or E horizon, and meeting the following requirements:

The plinthic horizon, if present, is not overlying or coincident with the upper part of the textural B horizon;

The gley horizon, if present, is not overlying or coincident with the upper part of the textural B horizon.

Scope – this class includes the soils that were previously classified as Podzólico Vermelho-Amarelo with low or high activity clay, a small part of the Terra Roxa Estruturada, Terra Roxa Estruturada Similar, of Terra Bruna Estruturada and Terra Bruna Estruturada Similar, mostly with a textural gradient required for a textural B horizon. In any case, it includes soils that had been classified as Eutrófico, Distrófico or Álico, Podzólico Bruno-Acinzentado, Podzólico Vermelho-Escuro, Podzólico Amarelo, Podzólico Acinzentado, and more recently, Alissolos with a textural B horizon.

Cambissolos

Concept – soils consisting of mineral material, with incipient B horizon underlying any type of surface horizon, provided that the requirements of the classes Vertissolos, Chernossolos, Plintossolos and Organossolos are not met in any case. The horizon sequence consists of A or histic, Bi, C, with or without R.

Due to the heterogeneity of the parent material, relief forms and climatic conditions, the characteristics of these soils vary greatly from one location to another. Thus, the class includes soils with strong to imperfect drainage, shallow to deep, from brown or yellowish brown to dark red, with high and low base saturation and chemical activity of the clay fraction.

The incipient B horizon (Bi) has a sandy loam or more clayey texture, and the clay contents of the solum are usually uniform and a slight decrease or increase in clay may occur from A to Bi. A marked difference of particle size between A and Bi is possible in soils developed from alluvial sediments or when there is a lithological discontinuity or stratification of the parent material.

The structure of the incipient B horizon (Bi) can be in blocks, granular or prismatic, with occurrence of soils without aggregates, with simple grain or massive structure.

A horizon with occurrence of plinthite or gleization may be found in soils of this class, provided it does not meet the requirements for the classes of Plintossolos or Gleissolos.

Some soils of this class have morphological characteristics similar to those of the Latossolos, but are distinguished by having, in the B horizon, one or more of the characteristics specified below, which are not compatible with highly developed soils:

Cation exchange capacity, without correction for carbon, of ≥ 17 cmolc kg⁻¹ clay; and/or

≥ 4% alterable primary minerals or ≥ 6% muscovite, determined in the sand fraction, but based on the fine earth fraction; and/or

Molecular ratio SiO₂/Al₂O₃ (Ki) > 2.2, determined in or corresponding to the clay fraction; and/or

Original rock structure, such as fine stratifications, saprolite or semi- or unweathered rock fragments, in ≥ 5% of the soil volume.

Definition – soils consisting of mineral material with an A or histic horizon with insufficient thickness to be allocated to the class of Organossolos, followed by an incipient B horizon and satisfying the following requirements:

The incipient B horizon does not coincide with a gley horizon within 50 cm from the soil surface;

The incipient B horizon does not coincide with a plinthic horizon;

The incipient B horizon does not coincide with a vertic horizon within 100 cm from the surface; and

Absence of the combination of a chernozemic A horizon and an incipient B horizon with high base saturation and high activity clay.

Scope – this class comprises the soils previously classified as Cambissolos, including those developed from alluvial sediments. Soils with a chernozemic A horizon and incipient B horizon with high base saturation and high activity clay are excluded from this class.

Chernossolos

Concept – soils consisting of mineral material with the differential characteristics: high base saturation and chernozemic A horizon overlying a textural B or incipient B horizon, both with high activity clay or overlying a carbonatic C, calcic or petrocalcic horizon or overlying rock, in case of high calcium carbonate concentration in the A horizon.

These soils are usually well to imperfectly drained, with sequences of A-Bt-C or A-Bi-C horizons, with or without a calcic horizon, and A-C or A-R, provided there is a carbonatic qualifier or calcic or petrocalcic horizon.

In this class, the occurrence of gleization or a gley horizon, friction surface or abrupt textural change is admitted, as long as the expression is quantitatively and qualitatively insufficient or the position within the horizon sequence in the profile is not diagnostic for a classification as Gleissolos, Vertissolos or Planossolos.

These soils can be from moderately acidic to strongly alkaline, with high activity clay, a cation exchange capacity that can reach > 100 cmolc kg⁻¹ clay, high base saturation, generally > 70%, with predominance of calcium or calcium and magnesium among the exchangeable cations.

In spite of the variable climatic conditions and different parent materials from which these soils are formed, their development depends on a set of conditions that favor the formation and persistence of a surface horizon rich in organic matter, with high calcium and magnesium contents and with the presence of 2:1 clay minerals, particularly of the smectite group.

Definition – soils consisting of mineral material and with high base saturation and a chernozemic A horizon followed by:

An incipient B or textural B horizon, both with high activity clay; or

A calcic or petrocalcic horizon or carbonatic qualifier, coinciding with a chernozemic A horizon and/or with the C horizon, admitting, between the two, a Bi horizon with a thickness of < 10 cm; or

A lithic or fragmentary lithic contact, provided the A horizon contains ≥ 150 g kg⁻¹ soil of CaCO₃ equivalent.

Scope – this class comprises the majority of soils formerly classified as Brunizém, Rendzina, Brunizém Avermelhado, Brunizém Hidromórfico and Cambissolos Eutróficos with high activity clay, combined with a chernozemic A horizon.

Espodossolos

Concept – soils consisting of mineral material with a spodic B horizon underlying the eluvial E horizon (albic or not) or an A horizon, which can be of any type, or a histic horizon with insufficient thickness for the class of Organossolos. These soils usually have a sequence of abruptly differentiated A, E, spodic B, and C horizons.

The color of the A horizon varies from gray to black, and of the E horizon from gray or light gray to almost white. The color of the spodic horizon varies from gray with dark or black shades to reddish or yellowish.

The solum texture of the B horizon is predominantly sandy, less commonly loamy and rarely clayey. Drainage is very variable, with a close relationship between depth, development degree, hardening or cementation of the spodic B horizon and soil drainage.

These soils generally have a very low fertility due to a poor nutrient reserve, are moderate to strongly acid, usually have low base saturation, and high levels of extractable aluminum are possible. A fragipan, duripan, a placic horizon or ortstein can be found.

Espodossolos are developed primarily from quartz-rich sandy materials under high moisture conditions, in tropical and subtropical climate, usually with a flat or gently undulating relief, in resurgence zones and depressions; however, they may also occur in areas with an undulating relief, in cold environments, with high moisture and upper-montane vegetation (Dias et al., 2003). In coastal regions, they are generally associated with a sparse vegetation broadly called Restinga. The Espodossolos that occur in the Amazon and the Coastal Tablelands are often associated with vegetation forms known as Campinarana and Muçununga, respectively.

Definition – soils consisting of mineral material, with a spodic B horizon immediately below the E, A or histic horizon within 200 cm from the surface or within 400 cm, if the sum of the A and E horizons or of the histic and E horizons exceeds a depth of 200 cm.

Scope – this class includes all soils previously classified as Podzol and Podzol Hidromórfico.

Gleissolos

Concept – includes hydromorphic, mineral soils, which have a gley horizon within 50 cm from the surface or at depths of > 50 cm and ≤ 150 cm, provided that immediately below an A or E horizon (with or without gleization)²⁷ or a histic horizon with insufficient thickness to be integrated in the class of Organossolos. The texture is not exclusively sandy in all horizons within the first 150 cm from the soil surface, or to a lithic or fragmentary lithic contact, nor is there a vertic horizon in diagnostic position for Vertissolos. If a planic, plinthic, concretionary or lithoplinthic horizon is present, it should occur at a depth of > 200 cm below the soil surface.

The soils of this class are permanently or periodically water-saturated, if not artificially drained. Saturation occurs by internal waterlogging or due to lateral flow of water in the soil. In any case, the soil water can ascend by capillary rise up to the surface.

Gleissolos are characterized by strong gleization due to the reducing environment, virtually free of dissolved oxygen, resulting from water-saturation lasting all year or at least several months.

The process of gleization induces grayish, bluish or greenish colors due to iron reduction and dissolution, allowing the expression of neutral colors of the clay minerals or the precipitation of ferrous compounds.

Under natural conditions, these are poorly or very poorly drained soils with a horizon sequence of A-Cg, A-Big-Cg, A-Btg-Cg, A-E-Btg-Cg, A-Eg-Bt-Cg, Ag-Cg, H-Cg, gray to black in the surface horizon, thickness normally between 10 cm and 50 cm and medium to high levels of organic carbon.

The gley horizon, which may be a C, B, E or A horizon, is predominantly bluer than 10Y, with rather low, close to neutral chromas.

These soils can occasionally have a sandy (sand or loamy sand) texture, in the surface horizons only, as long as followed by a gley horizon with a sandy loam or finer texture.

Aside from the A, H or E horizons that may be present, the structure in the C horizon is normally massive and may have cracks and a similar appearance to that of the prismatic structure when dry, or after exposure of a trench wall for a few days. When a B horizon is present, the structure is blocky or prismatic, composed or not of angular and subangular blocks. These soils may contain a sulfuric or calcic horizon, solodic, sodic or salic qualifier, or plinthite in insufficient quantity or non-diagnostic position for inclusion in the class of Plintossolos.

These soils were formed mainly from sediments, stratified or not, and subject to constant or periodic excess of water, which can occur in various situations. Commonly, they develop from recent sediments in the vicinity of watercourses and in alluvial/colluvial materials subject to hydromorphic conditions. They can also be formed in flat relief areas of fluvial, lacustrine or sea terraces, as well as in residual materials in depressions. They are occasionally formed in sloping areas under the influence of groundwater springs (resurgence zones or sources). These soils occur under hydrophilic or hygrophilous herbaceous, shrub or tree vegetation.

Definition – soils consisting of mineral material, with a gley horizon 50 cm below the surface or at a depth of > 50 cm and ≤ 150 cm, provided that immediately below the A or E horizons or a H horizon (histic) with insufficient thickness to define the class of Organossolos, satisfying the following requirements:

Absence of vertic horizon in diagnostic position for Vertissolos;

No plinthic, planic, concretionary or lithoplinthic horizon within 200 cm from the surface.

Scope – this class includes the soils previously classified as Glei Pouco Húmico, Glei Húmico, part of the Hidromórfico Cinzento (with no abrupt textural change), Glei Tiomórfico and Solonchak with a gley horizon.

Latossolos

Concept – soils consisting of mineral material, with a latosolic B horizon immediately below any of the types of diagnostic surface horizons, except the histic.

These soils are in an advanced weathering stage, very evolved as a result of vigorous transformations of the parent material. The soils are virtually devoid of primary or secondary minerals that are less weathering resistant. The cation exchange capacity of the clay fraction is low (< 17 cmolc kg⁻¹ clay without correction for carbon), admitting variations from predominantly kaolinitic soils, with higher Ki values of around 2.0 to a maximum of 2.2, to oxidic soils with extremely low Ki.

They vary from extremely well to well-drained, although soils with pale colors, with moderate or even imperfect drainage occur, indicating a certain degree of gleization during formation under current or past conditions.

The soils are usually very deep, with a solum thickness of rarely less than 1 m. They have a sequence of A, B, C horizons with little differentiation between the subhorizons, usually with diffuse or gradual transitions. In contrast with the darker A horizon, the B horizon has more vivid colors, ranging from yellow or even grayish brown to dusky red, in hues from 2.5YR to 10YR. The colors depend on the nature, form and amount of mineral constituents – especially the iron oxides and hydroxides – according to the conditions of water regime and soil drainage, the iron levels in the parent material and whether the hematite is inherited or not. In the C horizon, comparatively less colorful, the chromatic expression is quite variable, even heterogeneous, given its more saprolitic or sedimentary nature. The clay increase from A to B is low or non-existent, and the textural ratio B/A does not meet the requirements for a textural B horizon. In general, the content of the clay fraction in the solum increases gradually with depth or remains constant throughout the profile. Clay films, if present, are poor and weak. Typically, the mobility of clays in the B horizon is low, except for the atypical behavior in the case of soils developed from material with a lighter texture (quartz-rich sandy composition), of interactions with organic constituents of high activity or of soils with positive or null Δ pH.

The Latossolos are, in general, strongly acidic soils with low base saturation, dystrophic or aluminic. However, soils with medium and even high saturation also occur. The latter are usually found in zones (semi-arid or not) with a pronounced dry season, or under the influence of basic or calcareous rocks.

These soils are typical of equatorial and tropical regions, can also occur in subtropical areas, distributed mainly on large and old erosional surfaces, pediments or old river terraces, usually on flat and gently undulating relief, although they may occur in more rugged terrain, possibly in mountainous relief. They were derived from the most diverse types of rocks and sediments and under the most diverse conditions of climate and vegetation types.

Definition – soils consisting of mineral material with a latosolic B horizon immediately below any type of A horizon within 200 cm from the surface or within 300 cm, if the A horizon has a thickness of > 150 cm.

Scope –this class includes all the former Latossolos, except for some modalities previously identified as Latossolos plínticos.

Luvissolos

Concept – mineral soils, not hydromorphic, with textural B horizon with high activity clay and high base saturation, immediately below the A or E horizon.

These soils vary from well to imperfectly drained and are usually fairly shallow, with a sequence of A, Bt and C horizons and a clear differentiation between the A and Bt horizons due to the contrasting texture, color and/or structure. The transition to the textural B horizon is clear or abrupt, and an abrupt textural change occurs in a large part of the soils of this class. In the surface, stoniness may or may not be present, and the same applies to the presence of solodic or sodic qualifier in the subsurface.

The Bt horizon is reddish, yellowish and less often brownish or grayish. The structure is usually blocky, moderately or strongly developed, or prismatic, composed of angular and subangular blocks.

Luvissolos are moderately acidic to slightly alkaline, with low to non-existent levels of extractable aluminum and a high molecular ratio Ki in the Bt horizon, usually between 2.4 and 4.0, denoting the presence of a variable but considerable quantity of 2:1 clay minerals.

Definition – soils consisting of mineral material, with a textural B horizon, with high activity clay and high base saturation in most of the first 100 cm of the B horizon (including BA) and immediately below any type of A horizon except the chernozemic A or under the E horizon, and satisfying the following requirements:

Plinthic, vertic or planic horizons, if present, are not above or not coincident with the upper part of the textural B horizon;

A gley horizon, if present, must be below the textural B horizon and begins below a depth of 50 cm, not coinciding with the upper part of the latter.

Scope – this class comprises the soils that were classified by Embrapa Soils as Brunos Não Cálcicos, Podzólicos Vermelho-Amarelos Eutróficos with high activity clay and Podzólicos Bruno-Acinzentados Eutróficos and some Podzólicos Vermelho-Escuros Eutróficos with high activity clay.

Neossolos

Concept – soils consisting of mineral material or organic material that is not very thick, without significant changes in relation to the parent material due to the low intensity of pedogenetic processes, either due to inherent characteristics of the proper parent material (e.g., greater resistance to weathering or chemical–mineralogical composition), or due to the influence of other formation factors (climate, relief or time), which can prevent or limit soil development.

Neossolos have a horizon sequence of A-R, A-C-R, A-Cr-R, A-Cr, A-C, O-R or H-C, without meeting, however, the requirements for the identification of the classes of Chernossolos, Vertissolos, Plintossolos, Organossolos or Gleissolos. This class admits several types of surface horizons, including the O horizon with a thickness of < 20 cm when overlying rock or a humic or prominent A horizon with a thickness of > 50 cm when overlying the R, C or Cr layer.

Some soils can have a B horizon, but without meeting the requirements (very thin thickness, for example) of any type of diagnostic B horizon.

Definition – soils consisting of mineral material or of organic material less than 20 cm thick, without any kind of diagnostic B horizon and satisfying the following requirements:

Absence of a gley horizon immediately below the A horizon within 150 cm from the surface, except in the case of soils with a sand or loamy sand texture with virtually no weatherable primary minerals;

Absence of a vertic horizon immediately below the A horizon;

Absence of a plinthic horizon within 40 cm, or within 150 cm from the surface if immediately below the A or E horizons or if preceded by horizons with pale or variegated colors or abundant mottles;

Absence of a chernozemic A horizon with carbonatic qualifier or together with a calcic C horizon or with a carbonatic qualifier.

This class also comprises soils with an A horizon or a histic horizon with a thickness of < 20 cm followed by layer(s) with ≥ 90% (expressed in volume) of rock fragments or parent material, regardless of its resistance to weathering.

Scope – this class includes the soils that were previously recognized as Litossolos and Solos Litólicos, Regossolos, Solos Aluviais and Areias Quartzosas (Distróficas, Marinhas and Hidromórficas). It also comprises soils with a humic A or prominent A horizon, with a thickness of > 50 cm, followed by a lithic or fragmentary lithic contact or a horizon sequence of A, C or ACr.

Nitossolos

Concept – soils consisting of mineral material, with a nitic B horizon, with clayey or very fine clayey texture (clay contents ≥ 350 g kg⁻¹ ADFE) from the soil surface, with a subangular or angular blocky or prismatic structure of moderate or strong degree, with pronounced clay films and/or a retractable qualifier.

These soils have a clearly expressed B horizon in terms of the degree of structure development, associated with the presence of clay films, with a textural gradient of ≤ 1.5. In the Nitossolos with retractable qualifier, variations are admitted in structure, consistence, clay films and compression surfaces (criteria still in the validation phase).

This class excludes soils with significant increase in clay content in depth, as required in the definition of a textural B horizon, and a less pronounced differentiation of the horizons than of the Argissolos, with a clear or gradual transition from the A to B horizon and gradual or diffuse between the B subhorizons. The soils are deep, well drained, varying from red to brownish.

They are, in general, moderately acidic to acidic, with low activity clay or with the aluminic qualifier together with high activity clay, with a kaolinitic-oxidic composition. If they have the aluminic qualifier together with high activity clay, the clay mineralogy is characterized by the presence of hydroxy-Al interlayered 2:1 clay minerals (HIVE and HIS). They can have any kind of A horizon.

Definition – soils consisting of mineral material, with a nitic B horizon below the A horizon, with low activity clay or high activity clay, provided that combined with an aluminic qualifier, all contained in the major part of the first 100 cm of the B horizon (inclusive BA). The texture is clayey or very fine clayey (clay contents ≥ 350 g kg⁻¹ ADFE in the upper 100 cm from the soil surface) and the textural ratio is ≤ 1.5.

Polychromy (i.e., color variation within 150 cm from the soil surface), as described below, should be used as an additional criterion to distinguish between Nitossolos and Argissolos Vermelhos or Vermelho-Amarelos, in situations in which the other characteristics are coincident.

Nitossolos are soils that practically never have marked polychromy in the profile and must meet the following color criteria:

If the colors of the A and B, but not BC horizons are on the same hue page, variations of at most 2 units for value and/or 3 units for chroma are admitted²⁸;

For soils with the colors of the A and B horizons, except BC on two hue pages, a variation of ≤ 1 unit of value and ≤ 2 units of chroma is admitted²⁸;

For soils with colors of the A and B horizons, except BC, on more than two hue pages, no variation for value is accepted and a variation of ≤ 1 unit of chroma is admitted²⁸.

Scope – some soils fit in this class that were formerly mostly classified as Terra Roxa Estruturada, Terra Roxa Estruturada Similar, Terra Bruna Estruturada, Terra Bruna Estruturada Similar and some Podzólicos Vermelho-Escuros and Podzólicos Vermelho-Amarelos.

Organossolos

Concept – poorly evolved soils, with characteristics mainly determined by the organic material; black, very dark gray or brownish, due to the accumulation of plant residues, in varying degrees of decomposition, under limited drainage (from poorly to very poorly drained environments) or water saturated for only a few days in the rainy period, as in humid and cold environments of high altitudes

These soils are formed of organic material at locations where the climate varies from tropical with hydromorphy, in the coastal region and in deltas and lacustrine environments, to cold and moist, with high-montane vegetation. A histic horizon may be formed under conditions that favor anaerobiosis (H horizon) or of free drainage (O horizon). The parent material of these soils is composed of plant residues in different decomposition stages, usually in combination with mineral materials of variable particle size.

In environments characterized by strong hydromorphism, due to the high groundwater level for a large part of the year, the anaerobic conditions restrict the processes of organic matter mineralization and limit the pedogenetic development, leading to a substantial accumulation of plant residues.

In environments with a humid, cold climate and high-montane vegetation, the low temperature conditions favor organic material accumulation by the reduction of the biological activity. In these environments, the dystrophic conditions and high acidity may further restrict the transformation of organic matter.

This class includes soils with horizons of organic constitution (H or O), with a large proportion of plant residues in varied degrees of decomposition, which may overlie or be interwoven with mineral horizons or layers of varying thicknesses.

Usually, they are strongly acidic soils with high cation exchange capacity and low base saturation, with sporadic occurrences of medium or high base saturation. They can have a sulfuric horizon, sulfidic materials, a salic, sodic or solodic qualifier, which may be covered by a not very thick deposit (< 40 cm thick) of layers of mineral material.

The mineralization of organic matter and transformation of plant residues are slow under natural conditions. However, the drainage of these soils for agricultural or other purposes leads to the process of ground subsidence and accelerates the decomposition of organic matter, promoting its degradation. The composition of the plant material, the thickness of the deposited organic material, the climate and hydromorphic conditions and management intensity – drainage, liming and fertilization – determine the intensity of degradation of the Organossolos.

The criteria related to high Al contents in the soil (aluminic or alic) should not be applied to the organic horizons, once the methodology for Al extraction developed for soils with mineral material is not appropriate for soils of organic nature, resulting in an overestimation of the effect of Al toxicity (Perez et al., 2009). Various methods are being tested, but the results are not yet conclusive.

Organossolos typically occur in low areas of floodplains, depressions and resurgence zones, under hydrophilic or hygrophilous vegetation, be it of the grassland or forest type. They are also found in areas that are saturated with water for a few days (less than 30 consecutive days) in the rainy period, as in high altitude regions, with humid, cold climate and high-montane vegetation, and in this case usually directly overlying unfractured rocks, a C horizon or even a poorly developed B horizon.

Definition²⁹ – soils with a predominance of organic material blended with a greater or lesser proportion of mineral material and that meet the following requirements:

60 cm or thicker if 75% (expressed in volume) or more of the organic material consists of plant tissue in the form of residues of fine branches, trunk fragments, fine roots, tree bark, excluding live parts; or

Soils saturated with water for at most 30 consecutive days per year, during the rainiest period, with a histic O horizon, with the following thicknesses:

20 cm or more, when overlying a lithic or fragmentary lithic contact or a horizon or layer constituted by 90% or more (by volume) of mineral material with a diameter greater than 2 mm (gravels, pebbles and boulders); or

40 cm or more when overlying the horizons A, B or C; or

Soils saturated with water for the most part of the year, in most years, unless artificially drained, with presence of a histic H horizon with a thickness of ≥ 40 cm, either extending in a single section from the surface downwards, or cumulatively, within the 80 cm below the surface.

Scope – this class contains the Solos Orgânicos, Semiorgânicos, Solos Tiomórficos of organic or semi-organic constitution and part of the Solos Litólicos with a histic O horizon with a thickness of ≥ 20 cm.

Planossolos

Concept – imperfectly or poorly drained mineral soils, with an eluvial surface or subsurface horizon, with a lighter texture, in sharp contrast with the immediately underlying B horizon, dense, usually marked clay concentration, slow or very slow permeability, sometimes constituting a pan horizon, responsible for the formation of a (suspended) water saturated zone, with annual occurrence .

Planossolos may present any type of A horizon, followed or not by an E horizon, immediately above the planic B horizon, with a horizon sequence of A, AB or A, E (albic or not) or Eg, followed by Bt, Btg, Btn or Btng.

A strikingly distinctive characteristic is the clear differentiation between the A or E and B horizons, due to the abrupt textural change or abrupt transition coupled with a marked texture difference from the A to B horizon (Chapter 2, subitem h). A quite noticeable occurrence in dry soils is the exposure of a contact parallel to the horizons, forming an accentuated limit by setting a clear-cut contrast between the A or E and the B horizon.

Typically, one or more subsurface horizons are dense and may have a high content of dispersed clay, sometimes constituting a pan horizon, a condition of restricted water percolation, regardless of the position of the water table, causing water retention for some time above the B horizon, which is reflected in the features associated with excess moisture.

Typical of the B horizon is the presence of a strong and large structure in angular blocks, often with a cubic appearance or prismatic or columnar structure, at least in the upper part of this horizon. It usually has a hard to extremely hard consistence when dry.

Due to the effect of the cyclic duration of excess moisture, even when for short periods, the colors in the B horizon, and even in the lower part of the overlying horizon, are predominantly pale. They tend to be grayish or darkened, and neutral colors of reduction may be present or even predominant, with or without mottles, as specified for the planic B horizon.

Soils in this class may or may not have a calcic horizon, carbonatic qualifier, duripan with a sodic, solodic property, saline or salic qualifier. It may contain plinthite, but in quantity or position not diagnostic for allocation to the class of Plintossolos.

The soils of this class occur preferentially in areas with a flat or gently undulating topography, where the environmental conditions and the soil itself favor a periodic annual duration of excess water, albeit short, particularly in regions prone to prolonged drought and even under semi-arid climate conditions.

Soils in the lowlands, wetlands and depressions in a humid climate are truly hydromorphic, with a planic horizon that coincidentally meets the characteristics of a gley horizon. However, in semi-arid areas, and even in areas where the soil is exposed to water excess for only a short period, mainly where the relief is gently undulating, the soils are not actually hydromorphic.

Definition – soils consisting of mineral material with an A or E horizon and followed by a planic B horizon. In case of a planic horizon without sodic qualifier, the taxonomic precedence is given to the plinthic horizon.

Scope – this class includes the soils classified as Planossolos, Solonetz-Solodizado and part of the Hidromórficos Cinzentos.

Plintossolos

Concept – mineral soils formed under conditions of restricted water percolation exposed to a temporary effect of excess moisture, usually with imperfect or poor drainage, and basically characterized by strong plinthization, with or without petroplinthite under conditions that do not satisfy the requirements for the classes of Neossolos, Cambissolos, Luvissolos, Argissolos, Latossolos, Planossolos or Gleissolos.

These soils frequently have a textural B horizon over or coincident with a plinthic horizon or with a concretionary horizon, and soils with an incipient B, latosolic B, gley horizon, and soils with no B horizon also occur.

Usually, these soils are clearly differentiated, and the A horizon may be of any type, with a horizon sequence of A, AB followed by Bt, Bw, Bi, C or F or also A, E horizons, followed by Bt, C or F. The suffixes c or f accompany most of these horizons.

Although the color of these soils is highly variable, there is a predominance of pale colors, with or without mottles that are orange to red or variegated, above the diagnostic horizon (plinthic, concretionary or lithoplinthic). In some soils of this class, although their genesis is associated to excess moisture conditions or temporarily restricted water percolation, at present, drainage conditions may be good and they may be reddish in the major part of the profile.

Strongly acidic soils with low base saturation and low clay fraction activity are predominant. Nevertheless, soils with medium to high base saturation or high activity clay can occur (Anjos et al., 1995), as well as soils with solodic and sodic properties.

A major part of the soils of this class (soils with a plinthic horizon) may be present in terrains with wetlands, areas with flat to gently undulating and less frequently undulating relief, in geomorphic zones of depression. Plintossolos also occur on the lower third of slopes or in headwater areas under conditions of either oscillations of the water table, or of flooding or periodic flooding, as a result of restriction to percolation or water runoff.

Another part (soils with a concretionary horizon) have better drainage and occupy higher positions than soils with plinthic horizon. They are normally found on edges of plateaus and slightly dissected areas of plateaus and tablelands in the Central and Northern regions of Brazil.

These soils are typical of warm and humid areas, usually with a well-defined dry season or at least a period with marked decrease of rainfall. They also occur in the perhumid equatorial and more sporadically in the semi-arid zones.

The most extensive areas of soils with more restricted drainage are located in the Middle Amazon region (interfluves of the rivers Madeira, Purus, Juruá, Solimões and Negro), on the island of Marajó, in Amapá, in the Baixada Maranhense-Gurupi, in the Pantanal, on the floodplain of the Araguaia River, on the Bananal Island and in the region of Campo Maior of Piauí. Soils with better drainage, with a significant presence of petroplinthite in the profile, occur more commonly in the Central and Northern regions of Brazil, mainly in the states of Tocantins, Pará, Amazonas, Mato Grosso, Goiás, Piauí and Maranhão and in the Federal District.

Definition – soils consisting of mineral material, with a plinthic, lithoplinthic or concretionary horizon, meeting one of the following conditions:

Starting at ≤ 40 cm from the surface; or

Starting at ≤ 200 cm from the surface when preceded by a gley horizon or located immediately below the A or E or another horizon that is pale, variegated or contains abundant mottles.

When preceded by a pale horizon or layer (grayish or light yellowish), this should have hues and chromas according to the items (a) and (b) listed below, and reddish to yellowish mottles may or may not occur.

When preceded by variegated horizons or layers, at least one of the colors must satisfy items (a) and (b).

When preceded by horizons or layers with mottles, these should be abundant (> 20% by volume) in a reddish or yellowish matrix and the hues and chromas should be according to items (a) and (b).

Hue 5Y; or

Hues 7.5YR, 10YR or 2.5Y with chroma ≤ 4.

Scope – this class includes soils formerly known as Lateritas Hidromórficas, part of the Podzólicos plínticos, part of the Gleis Húmicos and Gleis Pouco Húmicos and some of the Latossolos plínticos. Also included are other soils classified in several studies as Concrecionários Indiscriminados, Concrecionários Lateríticos, Solos Concrecionários and Petroplintossolos.

Vertissolos

Concept – soils consisting of mineral material with occurrence of a vertic horizon and small textural variation along the profile, insufficient to characterize a textural B horizon. The volume changes markedly with the increase of water content in the soil, with deep cracks in the dry season and evidence of movement of the soil mass in the form of friction surfaces (slickensides). A gilgai microrelief may be present and inclined cuneiform structures forming an angle with the horizontal surface. These characteristics result from the large movement of soil mass, which shrinks and cracks when dry and expands when moist. The soil consistence is very plastic and very sticky due to the common presence of expandable clays or a mixture of these with other clay minerals.

They have a horizon sequence of A-Bv-C, A-Biv-C or A-Cv and range from fairly shallow to deep, although very shallow soils also occur. In terms of drainage, they vary from imperfectly to poorly drained, and occasionally, moderately drained. The color may be dark, grayish, yellowish or reddish. In terms of physical properties, the water permeability is very slow when moist. These soils have a high cation exchange capacity, high base saturation (> 50%) with high calcium and magnesium levels and a high ratio Ki (> 2.0). The most frequent pH reaction is in the range from neutral to alkaline, and can occur, less frequently, in the moderately acid range.

The part corresponding to the subsurface horizon that was already sufficiently transformed so as not be classified as saprolite (Cv, Ck, Crk etc.) is identified as Bv or Biv horizon, which has a prismatic structure composed of blocks or structure in angular and subangular or cuneiform or and/or parallelepiped blocks. The texture is usually clayey or very fine clayey, although it can be loamy (with a minimum clay content of 300 g kg⁻¹) in the surface horizons. The consistence of the dry soil varies from very hard to extremely hard, when moist from firm to very firm, and when wet it is very plastic and very sticky.

Vertissolos are soils normally developed in environments of sedimentary basins or from sediments with predominance of materials of fine particle size and with high calcium and magnesium levels or directly developed from calcium and magnesium-rich basic rocks. They occur in various climate types, from very humid (but with a defined dry season) to the driest, with considerable frequency in the sedimentary basins of the semi-arid region of Northeastern Brazil. With regard to the relief, these soils are distributed in flat or gently undulating areas and less frequently, in hilly areas, such as hillsides and hill tops.

In the taxonomy, the characteristics of the vertic horizon prevail, even when the soils have gley, calcic or duripan horizons; or solodic, sodic, saline or salic qualifiers.

Soils with a vertic horizon but that do not satisfy the definition of Vertissolos are considered intermediate to Vertissolos, as well as soils where the identification attributes of the class (cracks, slickensides, cuneiform and/or parallelepiped structures) are not found in sufficient quantity and distribution to characterize a vertic horizon. Such intermediate soils are labeled "vertissólicos" at the 4th level.

Definition – soils consisting of mineral material with a vertic horizon starting at ≤ 100 cm from the surface, with an insufficient textural ratio to characterize a textural B horizon and satisfying, in addition, the following requirements:

Clay content, after mixing and homogenization of the soil material of the upper 20 cm, of at least 300 g kg⁻¹ soil;

Vertical cracks in the dry period, at least 1 cm wide, reaching a depth of at least 50 cm from the surface, except in the case of fairly shallow soils, where the minimum limit is a depth of 30 cm;

Absence of material with a lithic or fragmentary lithic contact, petrocalcic or duripan horizon within the first 30 cm from the surface;

In irrigated or poorly drained areas (without apparent cracks), the coefficient of linear extensibility (COLE) must be ≥ 0.06 or the linear extensibility should be ≥ 6 cm;

Absence of any kind of diagnostic B horizon above the vertic horizon.

Scope – this class contains all Vertissolos, including the hydromorphic.

Notes

(24) Bases: order of assumptions that govern the formation of classes (Cline, 1963).

(25) Criteria: elements by which the classes are differentiated in the application of the system to the soils (Cline, 1963); i.e., attributes that distinguish the classes from the others of the same categorical level. They constitute the differential characteristics of the class.

(26) Designations as used by Cline (1949) and applied throughout the text.

(27) In some cases, the A or E horizons themselves can concomitantly be gley horizons.

(28) Acceptable are variations of one unit more than that indicated for intermediate soils (latossólicos, rúbricos etc.) or when the difference occurs between the surface A horizon and the horizon(s) of the lower part of the profile, at a depth of > 100 cm from the soil surface.

(29) In Chapter 1, a new definition for "organic material" was used, where one of the applied criteria was a threshold of organic carbon content (≥ 80 g kg⁻¹), evaluated in the ADFE fraction, based on the method adopted by Embrapa Soils and as proposed by Valladares (2003).

Chapter 4

Classification of soils from the 1st to 4th categorical level

The classification of a soil is based on the evaluation of the morphological, physical, chemical and mineralogical properties of the profile. Environmental aspects of the profile location such as climate, vegetation, relief, parent material, hydric conditions, external characteristics and soil-landscape relationships are also taken into consideration.

The classification begins with the morphological description of the soil profile and field sampling of material, which must be carried out according to the criteria established in the manuals (Lemos; Santos, 1996; IBGE, 2015; Santos et al., 2015), with the utmost zeal, patience and discretion to describe the profile as well as the landscape.

The morphological characteristics observed in the field need to be described extensively, in compliance with the manuals, with due diligence to accurately record the designation of the horizons of the profile (Larach et al., 1988; Santos et al., 2015), as well as all the common and extraordinary morphological characteristics. Any records of cracks in the soil, microrelief (gilgai), colors indicating oxidation and reduction, soil water level and fluctuation, cohesive or compressed horizons or layers, root depth in the profile, biological activity along the profile, and any unusual or extraordinary occurrences are highly relevant. It is important to associate the morphological characteristics to the depth of occurrence, with the purpose of defining the control section established for different classes at the different categorical levels.

All morphological characteristics are relevant to characterize and classify soils, but some are particularly indispensable, for example: the moist and dry colors of the surface horizons (H or O, A and AB), the moist colors of the subsurface horizons, according to the Munsell Soil Color Charts (1994), the texture, structure, clay films, consistence, transition, and characteristics such as nodules, concretions, slickensides, compression surfaces etc. These characteristics are indispensable to define the diagnostic horizons of the Brazilian System of Soil Classification (SiBCS). The final classification of a soil is only confirmed after the interpretation of comprehensive laboratory analyses related to the profile. Based thereon, it is very important to readjust the field identification of the horizons and suffixes as necessary.

A soil can be correctly classified using the classification key up to the 4th categorical level of the system. To initiate and proceed with the application of the key, it is presumed that system users have a thorough knowledge of the concepts and basic definitions outlined in Chapters 1 and 2 of this publication, with regard to the diagnostic attributes, other attributes, diagnostic surface horizons and diagnostic subsurface horizons.

Prior to the classification of a soil with the key, the surface and subsurface diagnostic horizons must first be identified, since the 1st categorical level is based on the presence or absence of these horizons and on additional attributes or properties recognizable in the field and complemented by results of chemical and physical analyses.

The classification key is organized so that each class takes precedence over the following one. Thus, step by step, one should proceed in the following order:

Start using the key at the order level and then search for the class whose definition and requirements are most compatible with the characteristics of the soil being classified;

After having found the class of the 1st categorical level, go to Chapter 3 for more comprehensive concepts and definitions, to check the classification of the respective soil at this level, by comparing the soil properties with the requirements of the class;

Once the class of the 1st categorical level is confirmed, move on to the 2nd level, and so on, up to the 4th categorical level, constantly bearing in mind the order of precedence for the soil classification. For all levels, that is, in the 2nd, 3rd and 4th category, the classes are listed in the text in a sequence arranged as a key for classification. For example, at the 2nd categorical level (suborders), the user must begin with the 1st suborder and keep eliminating one by one until finally finding the suborder with definition criteria that are compatible with what is observed in the soil being classified. This procedure is the same for the other two categorical levels (great groups and subgroups);

At the 5th categorical level, the classes comprise all differential characteristics accumulated from the 1st level onwards. At this point, the classes are formed by adding appropriate terms for the definition of classes after the determination of the 4th categorical level (subgroups), in other words, a particular family must always belong to a subgroup. The properties and differential characteristics for classification at this level are presented in Chapter 18, in the sequence in which they should be used to define the classes, which should be discriminated according to the explanations in that chapter;

The 6th categorical level will allow the subdivision of the 5th level (family) in homogeneous soil classes, according to concepts and criteria still being discussed. This level should be based on differential characteristics that influence land use and management and may be correlated with plant development. This level is expected to allow for most detailed interpretations of soil surveys for various purposes.

Whereas, at the higher categorical levels, the classes are discriminated by one or few diagnostic attributes (for example, Planossolos Háplicos Carbonáticos are differentiated from other soils of the same suborder by the carbonatic qualifier or a calcic horizon), some of these attributes can be resumed at the 6th categorical level, but with a lower amplitude or subdivision of the classes used at the higher levels.

Due to the lack of a national system of soil classification before the 1st edition of the SiBCS was released in 1999, it was not possible to establish classification criteria for the 6th level. Nevertheless, several detailed soil surveys were carried out in Brazil up to that date using the concept of series. In all of these surveys, the series were not defined according to criteria organized in a national taxonomic system. As a result of this lack of standardizing criteria, the literature contains reports of series with the same name grouping completely different soils and even soils of different orders.

The classification at the 6th categorical level requires an accurate consideration of the attributes used at the highest levels and a careful choice of diagnostic attributes that are readily observable in the field, accurately measurable and which, moreover, play a significant role in the soil behavior.

Note: Embrapa Soils is the institution designated to validate new classes proposed for the SiBCS, after previous analysis by the Executive Committee for Soil Classification.

It is to be expected that the effective and continued use of the SiBCS will reveal several soils that do not fall into the classes defined so far. In these cases, if a soil is geographically representative (estimated area > 200 ha), it is requested to send a detailed morphological description, the complete analytical data and the reasons for the impossibility of classifying the soil in an existing category of the SiBCS to the Executive Committee for Soil Classification (address p. 14).

For decimals resulting from calculations and analytical data, it is recommended to observe the standard rule of numeric rounding, where decimals > 0.5 are rounded up and those ≤ 0.5 down.

Key for the identification of soil classes

For the application of the key at the 1st categorical level (orders), some assumptions must be taken into consideration:

Observe the prevalence of horizons. Thus, if the key indicates a "soil with a textural B horizon", this implies that it is not coincident with a gley or plinthic horizon, because both take precedence over it. If a "soil with a planic B horizon with a sodic qualifier" is identified, this implies that the B horizon may be coincident with a plinthic or gley horizon, and so forth;

Observe that the first diagnostic subsurface horizon, in relation to the surface, takes precedence over others that may occur. For example, in the classes Argissolos and Nitossolos, a latosolic B horizon can occur below the textural B and nitic B horizons, respectively. In this case, the latosolic B has no taxonomic influence on the 1st categorical level, although it can be used as a discriminating factor at the lower categorical levels.

Under the humid tropical climate prevailing in Brazil, the effects of the biological activity and pedogenetic processes commonly reach deeper than 200 cm. Under these conditions, for practical reasons related to field work, the lower limit of the soil to be classified is arbitrarily fixed at 200 cm, except when:

The A horizon has a thickness of > 150 cm, as in certain Latossolos with a thick humic A horizon, for which the arbitrary limit is 300 cm; or

An E horizon is present in the sequum, and the thickness of the E added to that of the A horizon is ≥ 200 cm, and for which the arbitrary limit is 400 cm.

For certain characteristics, attributes and/or properties of the soil, specific control sections are used for classification purposes. These control sections are established in the keys for the identification of the soil classes (Chapters 4 to 17). However, it is recommended that, whenever possible, the description of deep soil profiles should reach a depth of 200 cm.

Key to classes of the 1st categorical level (orders)

The key contains brief definitions that allow the distinction of the orders from each other. The complete definition is included in the text of this publication (Chapter 3), and the user should consult the full text for a perfect understanding and classification of the order identified in the key.

At the 1st categorical level (order), the soils are classified in the following sequence:

Soils with a histic horizon that meets one of the following thickness criteria:

≥ 20 cm, when overlying a lithic or fragmentary lithic contact or a horizon or layer composed of mineral material with a diameter of > 2 mm (gravels, pebbles and boulders), occupying ≥ 90% (by volume); or

≥ 40 cm, continuous or cumulative, within the first 80 cm from the soil surface; or

≥ 60 cm, if ≥ 75% (by volume) of the horizon consists of plant tissue in the form of residues of fine branches, fine roots, tree barks etc., excluding live parts.

Organossolos (Chapter 14)

Other soils without a diagnostic B horizon that meet the following requirements:

Absence of a gley horizon within 50 cm from the surface, except in the case of soils with sand and loamy sand texture;

Absence of a plinthic horizon within 40 cm from the surface;

Absence of a vertic horizon immediately below the A horizon;

If a chernozemic A horizon is present, it should not be combined with the carbonatic qualifier and/or a calcic horizon.

Neossolos (Chapter 12)

Other soils with an insufficient textural ratio to classify a textural B that have a vertic horizon starting within 100 cm from the surface and that meet the following requirements:

Clay content, after mixing and homogenization of the soil material of the upper 20 cm, of at least 300 g kg⁻¹ soil;

Vertical cracks in the dry period, at least 1 cm wide, reaching a depth of ≥ 50 cm from the surface, except in the case of fairly shallow soils, where the minimum limit is a depth of 30 cm;

Absence of material with a lithic or fragmentary lithic contact, petrocalcic or duripan horizon within the first 30 cm from the surface;

In irrigated or poorly drained areas (without apparent cracks), the coefficient of linear extensibility (COLE) of the soil must be ≥ 0.06.

Vertissolos (Chapter 17)

Other soils with a spodic B horizon immediately below the E or A horizon.

Espodossolos (Chapter 8)

Other soils with a planic B that does not coincide with the plinthic horizon (with no sodic qualifier), immediately below the E or A horizon.

Planossolos (Chapter 15)

Other soils with a gley horizon starting within 50 cm from the surface or at depths of > 50 cm and ≤ 150 cm, provided that it is immediately below the A or E horizon or a histic horizon with a thickness of < 40 cm, without a plinthic, concretionary or lithoplinthic horizon within 200 cm from the surface or another diagnostic horizon above the gley horizon.

Gleissolos (Chapter 9)

Other soils with a latosolic B horizon immediately below the A horizon.

Latossolos (Chapter 10)

Other soils that have a chernozemic A horizon followed by: an incipient B or textural B horizon, both with high activity clay and high base saturation; or a Bi horizon with a thickness of < 10 cm or a C horizon, either calcic, petrocalcic or carbonatic; or a calcic horizon or carbonatic qualifier in the A horizon, followed by a lithic or fragmentary lithic contact.

Chernossolos (Chapter 7)

Other soils that have an incipient B horizon immediately below the A or a histic horizon with a thickness of < 40 cm, and plinthite and petroplinthite, if present, that do not meet the requirements for Plintossolos.

Cambissolos (Chapter 6)

Other soils with a plinthic horizon, which is not coincident with the planic B horizon with the sodic qualifier, or a litoplinthic or concretionary horizon, all starting at one of the following conditions.

Within 40 cm from the surface; or

Within 200 cm from the surface if preceded by a gley horizon, an A or E horizon or another horizon with pale colors, variegated or with mottles.

Plintossolos (Chapter 16)

Other soils that have a textural B horizon with high activity clay and high base saturation in most of the upper 100 cm of the B horizon (including BA), immediately below the A or E horizon.

Luvissolos (Chapter 11)

Other soils that contain 350 g kg-1 or more clay, possibly in the A horizon, with a nitic B horizon below the A horizon and with low activity clay or high activity clay, provided that combined with the aluminic qualifier, all included in the major part of the first 100 cm of the B horizon (including BA).

Nitossolos (Chapter 13)

Other soils that have a textural B horizon.

Argissolos (Chapter 5)

Chapter 5

Argissolos

Argissolos are soils composed of mineral material, which have a textural B horizon immediately below an A or E horizon, with low activity clay or with high activity clay, provided that coupled with low base saturation or with an aluminic qualifier in most of the B horizon, and which also meet the following requirements:

The plinthic horizon, if present, does not meet the criteria for Plintossolos;

The gley horizon, if present, does not meet the criteria for Gleissolos.

Classes of the 2nd categorical level (suborders)

1 ARGISSOLOS BRUNO-ACINZENTADOS³⁰

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Soils with a hue of 5YR or yellower, value of 3 to 4 and chroma ≤ 4 in most of the first 100 cm of the B horizon (including BA), with pronounced darkening of the upper part of that horizon, which must meet the following color criteria:

In the moist state, the values and/or chromas must be lower than those of the immediately underlying subhorizon; and

In the dry state, the values and/or chromas must be lower than those of at least one of the subhorizons above the darker B horizon, so that when the soil is dry, the presence of the dark subsurface horizon is clearly visible.

2 ARGISSOLOS ACINZENTADOS

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Soils that are grayish in most of the first 100 cm of the B horizon (including BA), with a hue of 7.5YR or yellower, values ≥ 5 and chromas < 4.

3 ARGISSOLOS AMARELOS

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Soils with a hue of 7.5YR or yellower in most of the first 100 cm of the B horizon (including BA), which do not fit in the previous classes.

4 ARGISSOLOS VERMELHOS

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Soils with a hue of 2.5YR or redder in most of the first 100 cm of the B horizon (including BA).

5 ARGISSOLOS VERMELHO-AMARELOS

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Other yellowish red and/or reddish yellow soils that do not fit in the previous classes.

Classes of the 3rd categorical level (great groups)

1 ARGISSOLOS BRUNO-ACINZENTADOS

1.1 ARGISSOLOS BRUNO-ACINZENTADOS Ta Alumínicos

Soils with high activity clay and an aluminic qualifier, in most of the first 100 cm of the B horizon (including BA).

1.2 ARGISSOLOS BRUNO-ACINZENTADOS Alumínicos

Soils with an aluminic qualifier in most of the first 100 cm of the B horizon (including BA).

1.3 ARGISSOLOS BRUNO-ACINZENTADOS Distróficos

Soils with a base saturation of < 50% in most of the first 100 cm of the B horizon (including BA).

2 ARGISSOLOS ACINZENTADOS

2.1 ARGISSOLOS ACINZENTADOS Distrocoesos

Soils with a base saturation of < 50% in most of the first 100 cm of the B horizon (including BA) and with a cohesive qualifier in one or more horizons, within 150 cm from the soil surface.

2.2 ARGISSOLOS ACINZENTADOS Distróficos

Soils with a base saturation of < 50% in most of the first 100 cm of the B horizon (including BA).

2.3 ARGISSOLOS ACINZENTADOS Eutróficos

Soils with a base saturation of ≥ 50% in most of the first 100 cm of the B horizon (including BA).

3 ARGISSOLOS AMARELOS

3.1 ARGISSOLOS AMARELOS Ta Alumínicos

Soils with high activity clay and an aluminic qualifier, in most of the first 100 cm of the B horizon (including BA).

3.2 ARGISSOLOS AMARELOS Alumínicos

Soils with an aluminic qualifier in most of the first 100 cm of the B horizon (including BA).

3.3 ARGISSOLOS AMARELOS Distrocoesos

Soils with a base saturation of < 50% in most of the first 100 cm of the B horizon (including BA) and with a cohesive qualifier in one or more horizons, within 150 cm from the soil surface.

3.4 ARGISSOLOS AMARELOS Distróficos

Soils with a base saturation of < 50% in most of the first 100 cm of the B horizon (including BA).

3.5 ARGISSOLOS AMARELOS Eutrocoesos

Soils with a base saturation of ≥ 50% in most of the first 100 cm of the B horizon (including BA) and with a cohesive qualifier in one or more horizons, within 150 cm from the soil surface.

3.6 ARGISSOLOS AMARELOS Eutróficos

Soils with a base saturation of ≥ 50% in most of the first 100 cm of the B horizon (including BA).

4 ARGISSOLOS VERMELHOS

4.1 ARGISSOLOS VERMELHOS Ta Alumínicos

Soils with high activity clay and an aluminic qualifier, in most of the first 100 cm of the B horizon (including BA).

4.2 ARGISSOLOS VERMELHOS Alumínicos

Soils with an aluminic qualifier in most of the first 100 cm of the B horizon (including BA).

4.3 ARGISSOLOS VERMELHOS Ta Distróficos

Soils with high activity clay and a base saturation of < 50%, both in most of the first 100 cm of the B horizon (including BA).

4.4 ARGISSOLOS VERMELHOS Distróficos

Soils with a base saturation of < 50% in most of the first 100 cm of the B horizon (including BA).

4.5 ARGISSOLOS VERMELHOS Eutroférricos

Soils with a base saturation of ≥ 50% and Fe2O3 (by H2SO4) contents from 180 g kg⁻¹ to < 360 g kg⁻¹ soil, both in most of the first 100 cm of the B horizon (including BA).

4.6 ARGISSOLOS VERMELHOS Eutróficos

Soils with a base saturation of ≥ 50% in most of the first 100 cm of the B horizon (including BA).

5 ARGISSOLOS VERMELHO-AMARELOS

5.1 ARGISSOLOS VERMELHO-AMARELOS Ta Alumínicos

Soils with high activity clay and an aluminic qualifier in most of the first 100 cm of the B horizon (including BA).

5.2 ARGISSOLOS VERMELHO-AMARELOS Alumínicos

Soils with an aluminic qualifier in most of the first 100 cm of the B horizon (including BA).

5.3 ARGISSOLOS VERMELHO-AMARELOS Ta Distróficos

Soils with high activity clay and a base saturation of < 50%, both in most of the first 100 cm of the B horizon (including BA).

5.4 ARGISSOLOS VERMELHO-AMARELOS Distróficos

Soils with a base saturation of < 50% in most of the first 100 cm of the B horizon (including BA).

5.5 ARGISSOLOS VERMELHO-AMARELOS Eutróficos

Soils with a base saturation of ≥ 50% in most of the first 100 cm of the B horizon (including BA).

Classes of the 4th categorical level (subgroups)

1.1 ARGISSOLOS BRUNO-ACINZENTADOS Ta Alumínicos

1.1.1 ARGISSOLOS BRUNO-ACINZENTADOS Ta Alumínicos abrúpticos

Soils with an abrupt textural change.

1.1.2 ARGISSOLOS BRUNO-ACINZENTADOS Ta Alumínicos espesso-húmicos

Soils with a humic A horizon and a carbon content of ≥ 10 g kg⁻¹ to a depth of ≥ 80 cm.

1.1.3 ARGISSOLOS BRUNO-ACINZENTADOS Ta Alumínicos húmicos

Soils with a humic A horizon.

1.1.4 ARGISSOLOS BRUNO-ACINZENTADOS Ta Alumínicos típicos

Other soils that do not fit in the previous classes.

1.2 ARGISSOLOS BRUNO-ACINZENTADOS Alumínicos

1.2.1 ARGISSOLOS BRUNO-ACINZENTADOS Alumínicos abrúpticos

Soils with an abrupt textural change.

1.2.2 ARGISSOLOS BRUNO-ACINZENTADOS Alumínicos típicos

Other soils that do not fit in the previous class.

1.3 ARGISSOLOS BRUNO-ACINZENTADOS Distróficos

1.3.1 ARGISSOLOS BRUNO-ACINZENTADOS Distróficos abrúpticos

Soils with an abrupt textural change.

1.3.2 ARGISSOLOS BRUNO-ACINZENTADOS Distróficos típicos

Other soils that do not fit in the previous class.

2.1 ARGISSOLOS ACINZENTADOS Distrocoesos

2.1.1 ARGISSOLOS ACINZENTADOS Distrocoesos arênicos

Soils with a sandy texture from the surface to a depth of ≥ 50 cm and ≤ 100 cm (Jacomine, 1986a, profile 82).

2.1.2 ARGISSOLOS ACINZENTADOS Distrocoesos abrúpticos dúricos

Soils with an abrupt textural change and a duric qualifier in one or more horizons or layers, within 150 cm from the soil surface (Araújo Filho, 2003, p. 215, profile 13).

2.1.3 ARGISSOLOS ACINZENTADOS Distrocoesos abrúpticos fragipânicos

Soils with an abrupt textural change and a fragipan in one or more horizons or layers, both within 150 cm from the soil surface.

2.1.4 ARGISSOLOS ACINZENTADOS Distrocoesos abrúpticos

Soils with an abrupt textural change.

2.1.5 ARGISSOLOS ACINZENTADOS Distrocoesos dúricos

Soils with a duric qualifier in one or more horizons or layers, within 150 cm from the soil surface (Araújo Filho, 2003, p. 205, profile 8).

2.1.6 ARGISSOLOS ACINZENTADOS Distrocoesos fragipânicos

Soils with a fragipan in one or more horizons or layers, within 150 cm from the soil surface (Jacomine et al., 1975a, profile 28).

2.1.7 ARGISSOLOS ACINZENTADOS Distrocoesos plintossólicos

Soils with a plinthic qualifier or plinthic horizon in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

2.1.8 ARGISSOLOS ACINZENTADOS Distrocoesos latossólicos

Soils with a latosolic B horizon below the textural B horizon, within 150 cm from the soil surface.

2.1.9 ARGISSOLOS ACINZENTADOS Distrocoesos típicos

Other soils that do not fit in the previous classes.

2.2 ARGISSOLOS ACINZENTADOS Distróficos

2.2.1 ARGISSOLOS ACINZENTADOS Distróficos arênicos

Soils with a sandy texture from the surface to a depth of ≥ 50 cm and ≤ 100 cm.

2.2.2 ARGISSOLOS ACINZENTADOS Distróficos abrúpticos dúricos

Soils with an abrupt textural change and a duric qualifier in one or more horizons or layers, within 150 cm from the soil surface.

2.2.3 ARGISSOLOS ACINZENTADOS Distróficos abrúpticos fragipânicos

Soils with an abrupt textural change and a fragipan in one or more horizons or layers, both within 150 cm from the soil surface.

2.2.4 ARGISSOLOS ACINZENTADOS Distróficos abrúpticos

Soils with an abrupt textural change.

2.2.5 ARGISSOLOS ACINZENTADOS Distróficos dúricos

Soils with a duric qualifier in one or more horizons or layers, within 150 cm from the soil surface.

2.2.6 ARGISSOLOS ACINZENTADOS Distróficos fragipânicos

Soils with a fragipan in one or more horizons or layers, within 150 cm from the soil surface.

2.2.7 ARGISSOLOS ACINZENTADOS Distróficos plintossólicos

Soils with a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

2.2.8 ARGISSOLOS ACINZENTADOS Distróficos latossólicos

Soils with a latosolic B horizon below the textural B horizon, within 150 cm from the soil surface.

2.2.9 ARGISSOLOS ACINZENTADOS Distróficos típicos

Other soils that do not fit in the previous classes.

2.3 ARGISSOLOS ACINZENTADOS Eutróficos

2.3.1 ARGISSOLOS ACINZENTADOS Eutróficos abrúpticos

Soils with an abrupt textural change.

2.3.2 ARGISSOLOS ACINZENTADOS Eutróficos plintossólicos

Soils with a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

2.3.3 ARGISSOLOS ACINZENTADOS Eutróficos típicos

Other soils that do not fit in the previous classes.

3.1 ARGISSOLOS AMARELOS Ta Alumínicos

3.1.1 ARGISSOLOS AMARELOS Ta Alumínicos saprolíticos abrúpticos endorredóxicos

Soils with a Cr (soft) horizon and no fragmentary lithic or lithic contact, all within 100 cm from the soil surface, with a redoxic qualifier at a depth of > 50 cm and ≤ 150 cm from the soil surface, and with an abrupt textural change (Costa, 2012, profile P1).

3.1.2 ARGISSOLOS AMARELOS Ta Alumínicos abrúpticos

Soils with an abrupt textural change.

3.1.3 ARGISSOLOS AMARELOS Ta Alumínicos plintossólicos

Soils with a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

3.1.4 ARGISSOLOS AMARELOS Ta Alumínicos epirredóxicos

Soils with a redoxic qualifier within 50 cm from the soil surface.

3.1.5 ARGISSOLOS AMARELOS Ta Alumínicos endorredóxicos

Soils with a redoxic qualifier at a depth of > 50 cm and ≤ 150 cm from the soil surface (Costa, 2012, profile P2).

3.1.6 ARGISSOLOS AMARELOS Ta Alumínicos típicos

Other soils that do not fit in the previous classes.

3.2 ARGISSOLOS AMARELOS Alumínicos

3.2.1 ARGISSOLOS AMARELOS Alumínicos abrúpticos

Soils with an abrupt textural change.

3.2.2 ARGISSOLOS AMARELOS Alumínicos plintossólicos

Soils with a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

3.2.3 ARGISSOLOS AMARELOS Alumínicos epirredóxicos

Soils with a redoxic qualifier within 50 cm from the soil surface.

3.2.4 ARGISSOLOS AMARELOS Alumínicos endorredóxicos

Soils with a redoxic qualifier at a depth of > 50 cm and ≤ 150 cm from the soil surface.

3.2.5 ARGISSOLOS AMARELOS Alumínicos típicos

Other soils that do not fit in the previous classes.

3.3 ARGISSOLOS AMARELOS Distrocoesos

3.3.1 ARGISSOLOS AMARELOS Distrocoesos solódicos abrúpticos

Soils with an abrupt textural change and a solodic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

3.3.2 ARGISSOLOS AMARELOS Distrocoesos arênicos fragipânicos

Soils with a sandy texture from the surface to a depth of ≥ 50 cm and ≤ 100 cm and with a fragipan in one or more horizons or layers, within 150 cm from the soil surface.

3.3.3 ARGISSOLOS AMARELOS Distrocoesos arênicos

Soils with a sandy texture from the surface to a depth of ≥ 50 cm and ≤ 100 cm.

3.3.4 ARGISSOLOS AMARELOS Distrocoesos abrúpticos fragipânicos espodossólicos

Soils with an abrupt textural change and a fragipan in one or more horizons or layers and with a spodic qualifier, all within 150 cm from the soil surface.

3.3.5 ARGISSOLOS AMARELOS Distrocoesos abrúpticos fragipânicos

Soils with an abrupt textural change and a fragipan in one or more horizons or layers, both within 150 cm from the soil surface.

3.3.6 ARGISSOLOS AMARELOS Distrocoesos abrúpticos petroplínticos

Soils with an abrupt textural change and concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons, in a non-diagnostic position for Plintossolos Pétricos, all within 150 cm from the soil surface.

3.3.7 ARGISSOLOS AMARELOS Distrocoesos abrúpticos plintossólicos

Soils with an abrupt textural change and a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

3.3.8 ARGISSOLOS AMARELOS Distrocoesos abrúpticos espodossólicos

Soils with an abrupt textural change and a spodic qualifier, within 150 cm from the soil surface.

3.3.9 ARGISSOLOS AMARELOS Distrocoesos abrúpticos

Soils with an abrupt textural change.

3.3.10 ARGISSOLOS AMARELOS Distrocoesos plácicos fragipânicos

Soils with a fragipan in one or more horizons or layers and a placic horizon, both within 150 cm from the soil surface (Araújo Filho, 2003, p. 202, profile 7).

3.3.11 ARGISSOLOS AMARELOS Distrocoesos fragipânicos plintossólicos

Soils with a fragipan and a plinthic qualifier in one or more horizons or layers, or a plinthic horizon, in a non-diagnostic position for Plintossolos, all within 150 cm from the soil surface.

3.3.12 ARGISSOLOS AMARELOS Distrocoesos fragipânicos espodossólicos

Soils with a fragipan in one or more horizons or layers and a spodic qualifier, both within 150 cm from the soil surface.

3.3.13 ARGISSOLOS AMARELOS Distrocoesos fragipânicos planossólicos

Soils with a fragipan and a planic qualifier in one or more horizons or layers, both within 150 cm from the soil surface.

3.3.14 ARGISSOLOS AMARELOS Distrocoesos fragipânicos

Soils with a fragipan in one or more horizons or layers within 150 cm from the soil surface.

3.3.15 ARGISSOLOS AMARELOS Distrocoesos plintossólicos

Soils with a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

3.3.16 ARGISSOLOS AMARELOS Distrocoesos espodossólicos

Soils with a spodic qualifier within 150 cm from the soil surface.

3.3.17 ARGISSOLOS AMARELOS Distrocoesos planossólicos

Soils with a planic qualifier within 150 cm from the soil surface.

3.3.18 ARGISSOLOS AMARELOS Distrocoesos latossólicos

Soils with a latosolic B horizon below the textural B horizon, within 150 cm from the soil surface.

3.3.19 ARGISSOLOS AMARELOS Distrocoesos epirredóxicos

Soils with a redoxic qualifier within 50 cm from the soil surface.

3.3.20 ARGISSOLOS AMARELOS Distrocoesos endorredóxicos

Soils with a redoxic qualifier at a depth of > 50 cm and ≤ 150 cm from the soil surface.

3.3.21 ARGISSOLOS AMARELOS Distrocoesos típicos

Other soils that do not fit in the previous classes.

3.4 ARGISSOLOS AMARELOS Distróficos

3.4.1 ARGISSOLOS AMARELOS Distróficos abrúpticos

Soils with an abrupt textural change.

3.4.2 ARGISSOLOS AMARELOS Distróficos gleissólicos

Soils with a gley horizon in a non-diagnostic position for Gleissolos, within 150 cm from the soil surface.

3.4.3 ARGISSOLOS AMARELOS Distróficos plintossólicos antrópicos

Soils with an anthropic A horizon and a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface (Reunião..., 2015, profile RR01).

3.4.4 ARGISSOLOS AMARELOS Distróficos plintossólicos

Soils with a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

3.4.5 ARGISSOLOS AMARELOS Distróficos cambissólicos

Soils with ≥ 4% visible alterable minerals (discernible by the naked eye or with a 10× lens) and/or ≥ 5% rock fragments in the B horizon (excluding BC or B/C), both within 150 cm from the soil surface.

3.4.6 ARGISSOLOS AMARELOS Distróficos típicos

Other soils that do not fit in the previous classes.

3.5 ARGISSOLOS AMARELOS Eutrocoesos

3.5.1 ARGISSOLOS AMARELOS Eutrocoesos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.5.2 ARGISSOLOS AMARELOS Eutrocoesos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.5.3 ARGISSOLOS AMARELOS Eutrocoesos solódicos plintossólicos planossólicos

Soils with a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, and planic and solodic qualifiers in one or more horizons or layers, all within 150 cm from the soil surface.

3.5.4 ARGISSOLOS AMARELOS Eutrocoesos abrúpticos plintossólicos

Soils with an abrupt textural change and a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

3.5.5 ARGISSOLOS AMARELOS Eutrocoesos abrúpticos

Soils with an abrupt textural change.

3.5.6 ARGISSOLOS AMARELOS Eutrocoesos fragipânicos

Soils with a fragipan in one or more horizons or layers within 150 cm from the soil surface.

3.5.7 ARGISSOLOS AMARELOS Eutrocoesos plintossólicos

Soils with a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

3.5.8 ARGISSOLOS AMARELOS Eutrocoesos típicos

Other soils that do not fit in the previous classes.

3.6 ARGISSOLOS AMARELOS Eutróficos

3.6.1 ARGISSOLOS AMARELOS Eutróficos solódicos

Soils with a solodic qualifier in one or more horizons within 150 cm from the soil surface.

3.6.2 ARGISSOLOS AMARELOS Eutróficos abrúpticos plintossólicos

Soils with an abrupt textural change and a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface (Reunião..., 1998, p. 96, profile 17).

3.6.3 ARGISSOLOS AMARELOS Eutróficos abrúpticos

Soils with an abrupt textural change.

3.6.4 ARGISSOLOS AMARELOS Eutróficos plintossólicos

Soils with a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

3.6.5 ARGISSOLOS AMARELOS Eutróficos planossólicos

Soils with a planic qualifier within 150 cm from the soil surface.

3.6.6 ARGISSOLOS AMARELOS Eutróficos típicos

Other soils that do not fit in the previous classes.

4.1 ARGISSOLOS VERMELHOS Ta Alumínicos

4.1.1 ARGISSOLOS VERMELHOS Ta Alumínicos abrúpticos

Soils with an abrupt textural change.

4.1.2 ARGISSOLOS VERMELHOS Ta Alumínicos plintossólicos

Soils with a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

4.1.3 ARGISSOLOS VERMELHOS Ta Alumínicos nitossólicos

Soils with a morphology (structure and clay films) similar to that of Nitossolos, differing from them in having a B/A textural ratio of > 1.5 and/or the presence of polychromy, within 150 cm from the soil surface.

4.1.4 ARGISSOLOS VERMELHOS Ta Alumínicos epirredóxicos

Soils with a redoxic qualifier within 50 cm from the soil surface.

4.1.5 ARGISSOLOS VERMELHOS Ta Alumínicos endorredóxicos

Soils with a redoxic qualifier at a depth of > 50 cm and ≤ 150 cm from the soil surface.

4.1.6 ARGISSOLOS VERMELHOS Ta Alumínicos típicos

Other soils that do not fit in the previous classes.

4.2 ARGISSOLOS VERMELHOS Alumínicos

4.2.1 ARGISSOLOS VERMELHOS Alumínicos abrúpticos

Soils with an abrupt textural change (Lemos et al., 1960, profile 3).

4.2.2 ARGISSOLOS VERMELHOS Alumínicos plintossólicos

Soils with a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

4.2.3 ARGISSOLOS VERMELHOS Alumínicos nitossólicos

Soils with a morphology (structure and clay films) similar to that of Nitossolos, differing from them in having a B/A textural ratio of > 1.5 and/or the presence of polychromy, within 150 cm from the soil surface (Reunião..., 2010a, profile AC 06).

4.2.4 ARGISSOLOS VERMELHOS Alumínicos epirredóxicos

Soils with a redoxic qualifier within 50 cm from the soil surface.

4.2.5 ARGISSOLOS VERMELHOS Alumínicos endorredóxicos

Soils with a redoxic qualifier at a depth of > 50 cm and ≤ 150 cm from the soil surface.

4.2.6 ARGISSOLOS VERMELHOS Alumínicos sômbricos

Soils with a sombric qualifier, starting within 150 cm from the soil surface (Lunardi Neto, 2012, p. 149, profile PVa).

4.2.7 ARGISSOLOS VERMELHOS Alumínicos típicos

Other soils that do not fit in the previous classes.

4.3 ARGISSOLOS VERMELHOS Ta Distróficos

4.3.1 ARGISSOLOS VERMELHOS Ta Distróficos abrúpticos

Soils with an abrupt textural change.

4.3.2 ARGISSOLOS VERMELHOS Ta Distróficos epirredóxicos

Soils with a redoxic qualifier within 50 cm from the soil surface.

4.3.3 ARGISSOLOS VERMELHOS Ta Distróficos endorredóxicos

Soils with a redoxic qualifier at a depth of > 50 cm and ≤ 150 cm from the soil surface.

4.3.4 ARGISSOLOS VERMELHOS Ta Distróficos típicos

Other soils that do not fit in the previous classes.

4.4 ARGISSOLOS VERMELHOS Distróficos

4.4.1 ARGISSOLOS VERMELHOS Distróficos espessarênicos

Soils with a sandy texture from the surface to a depth of > 100 cm and ≤ 200 cm.

4.4.2 ARGISSOLOS VERMELHOS Distróficos arênicos

Soils with a sandy texture from the surface to a depth of ≥ 50 cm and ≤ 100 cm.

4.4.3 ARGISSOLOS VERMELHOS Distróficos abrúpticos plintossólicos

Soils with an abrupt textural change and a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

4.4.4 ARGISSOLOS VERMELHOS Distróficos abrúpticos

Soils with an abrupt textural change.

4.4.5 ARGISSOLOS VERMELHOS Distróficos plintossólicos

Soils with a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

4.4.6 ARGISSOLOS VERMELHOS Distróficos planossólicos

Soils with a planic qualifier within 150 cm from the soil surface.

4.4.7 ARGISSOLOS VERMELHOS Distróficos nitossólicos

Soils with a morphology (structure and clay films) similar to that of Nitossolos, differing from them in having a B/A textural ratio of > 1.5 and/or the presence of polychromy, within 150 cm from the soil surface.

4.4.8 ARGISSOLOS VERMELHOS Distróficos latossólicos

Soils with a latosolic B horizon below the textural B horizon within 150 cm from the soil surface.

4.4.9 ARGISSOLOS VERMELHOS Distróficos típicos

Other soils that do not fit in the previous classes.

4.5 ARGISSOLOS VERMELHOS Eutroférricos

4.5.1 ARGISSOLOS VERMELHOS Eutroférricos saprolíticos abrúpticos

Soils with a Cr (soft) horizon and no fragmentary lithic or lithic contact, all within 100 cm from the soil surface, and an abrupt textural change (Larach et al., 1984, v. 1, p. 388, profile 49).

4.5.2 ARGISSOLOS VERMELHOS Eutroférricos abrúpticos

Soils with an abrupt textural change.

4.5.3 ARGISSOLOS VERMELHOS Eutroférricos nitossólicos chernossólicos

Soils with a morphology (structure and clay films) similar to that of Nitossolos, differing from them in having a B/A textural ratio of > 1.5 and/or the presence of polychromy within 150 cm from the soil surface, and a chernozemic A horizon and clay activity ≥ 20 cmolc kg⁻¹ clay in most of the first 100 cm of the B horizon (including BA) (Oliveira, 1999a, p. 129, profile IAC 1.375).

4.5.4 ARGISSOLOS VERMELHOS Eutroférricos nitossólicos

Soils with a morphology (structure and clay films) similar to that of Nitossolos, differing from them in having a B/A textural ratio of > 1.5 and/or the presence of polychromy within 150 cm from the soil surface.

4.5.5 ARGISSOLOS VERMELHOS Eutroférricos latossólicos

Soils with a latosolic B horizon below the textural B horizon within 150 cm from the soil surface.

4.5.6 ARGISSOLOS VERMELHOS Eutroférricos típicos

Other soils that do not fit in the previous classes.

4.6 ARGISSOLOS VERMELHOS Eutróficos

4.6.1 ARGISSOLOS VERMELHOS Eutróficos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.6.2 ARGISSOLOS VERMELHOS Eutróficos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.6.3 ARGISSOLOS VERMELHOS Eutróficos saprolíticos

Soils with a Cr (soft) horizon and no fragmentary lithic or lithic contact, all within 100 cm from the soil surface.

4.6.4 ARGISSOLOS VERMELHOS Eutróficos espessarênicos

Soils with a sandy texture from the surface to a depth of > 100 cm and ≤ 200 cm.

4.6.5 ARGISSOLOS VERMELHOS Eutróficos arênicos

Soils with a sandy texture from the surface to a depth of ≥ 50 cm and ≤ 100 cm.

4.6.6 ARGISSOLOS VERMELHOS Eutróficos solódicos abrúpticos plintossólicos

Soils with an abrupt textural change and a plinthic qualifier or plinthic horizon in a non-diagnostic position for Plintossolos and a solodic qualifier in one or more horizons or layers, all within 150 cm from the soil surface.

4.6.7 ARGISSOLOS VERMELHOS Eutróficos solódicos abrúpticos

Soils with an abrupt textural change and a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

4.6.8 ARGISSOLOS VERMELHOS Eutróficos abrúpticos plintossólicos

Soils with an abrupt textural change and a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

4.6.9 ARGISSOLOS VERMELHOS Eutróficos abrúpticos latossólicos antrópicos

Soils with an abrupt textural change and an anthropic A and a latosolic B horizon below the textural B within 150 cm from the soil surface (Reunião..., 2017, profile RO-08).

4.6.10 ARGISSOLOS VERMELHOS Eutróficos abrúpticos chernossólicos

Soils with an abrupt textural change and a chernozemic A horizon and clay activity ≥ 20 cmolc kg⁻¹ clay in most of the first 100 cm of the B horizon (including BA).

4.6.11 ARGISSOLOS VERMELHOS Eutróficos abrúpticos

Soils with an abrupt textural change.

4.6.12 ARGISSOLOS VERMELHOS Eutróficos luvissólicos

Soils with clay activity ≥ 20 cmolc kg⁻¹ clay and sum of bases ≥ 5.0 cmolc kg⁻¹, both in most of the first 100 cm of the B horizon (including BA).

4.6.13 ARGISSOLOS VERMELHOS Eutróficos nitossólicos

Soils with a morphology (structure and clay films) similar to that of Nitossolos, differing from them in having a B/A textural ratio of > 1.5 and/or the presence of polychromy within 150 cm from the soil surface.

4.6.14 ARGISSOLOS VERMELHOS Eutróficos latossólicos

Soils with a latosolic B horizon below the textural B horizon within 150 cm from the soil surface.

4.6.15 ARGISSOLOS VERMELHOS Eutróficos chernossólicos

Soils with a chernozemic A horizon and clay activity ≥ 20 cmolc kg⁻¹ clay in most of the first 100 cm of the B horizon (including BA).

4.6.16 ARGISSOLOS VERMELHOS Eutróficos típicos

Other soils that do not fit in the previous classes.

5.1 ARGISSOLOS VERMELHO-AMARELOS Ta Alumínicos

5.1.1 ARGISSOLOS VERMELHO-AMARELOS Ta Alumínicos abrúpticos

Soils with an abrupt textural change.

5.1.2 ARGISSOLOS VERMELHO-AMARELOS Ta Alumínicos plintossólicos

Soils with a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

5.1.3 ARGISSOLOS VERMELHO-AMARELOS Ta Alumínicos epirredóxicos

Soils with a redoxic qualifier within 50 cm from the soil surface.

5.1.4 ARGISSOLOS VERMELHO-AMARELOS Ta Alumínicos endorredóxicos

Soils with a redoxic qualifier at a depth of > 50 cm and ≤ 150 cm from the soil surface.

5.1.5 ARGISSOLOS VERMELHO-AMARELOS Ta Alumínicos típicos

Other soils that do not fit in the previous classes.

5.2 ARGISSOLOS VERMELHO-AMARELOS Alumínicos

5.2.1 ARGISSOLOS VERMELHO-AMARELOS Alumínicos abrúpticos

Soils with an abrupt textural change.

5.2.2 ARGISSOLOS VERMELHO-AMARELOS Alumínicos plintossólicos

Soils with a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

5.2.3 ARGISSOLOS VERMELHO-AMARELOS Alumínicos epirredóxicos

Soils with a redoxic qualifier within 50 cm from the soil surface.

5.2.4 ARGISSOLOS VERMELHO-AMARELOS Alumínicos endorredóxicos

Soils with a redoxic qualifier at a depth of > 50 cm and ≤ 150 cm from the soil surface.

5.2.5 ARGISSOLOS VERMELHO-AMARELOS Alumínicos típicos

Other soils that do not fit in the previous classes.

5.3 ARGISSOLOS VERMELHO-AMARELOS Ta Distróficos

5.3.1 ARGISSOLOS VERMELHO-AMARELOS Ta Distróficos abrúpticos

Soils with an abrupt textural change.

5.3.2 ARGISSOLOS VERMELHO-AMARELOS Ta Distróficos epirredóxicos

Soils with a redoxic qualifier within 50 cm from the soil surface.

5.3.3 ARGISSOLOS VERMELHO-AMARELOS Ta Distróficos endorredóxicos

Soils with a redoxic qualifier at a depth of > 50 cm and ≤ 150 cm from the soil surface.

5.3.4 ARGISSOLOS VERMELHO-AMARELOS Ta Distróficos típicos

Other soils that do not fit in the previous classes.

5.4 ARGISSOLOS VERMELHO-AMARELOS Distróficos

5.4.1 ARGISSOLOS VERMELHO-AMARELOS Distróficos espessarênicos abrúpticos

Soils with an abrupt textural change and a sandy texture from the soil surface to a depth of > 100 cm and ≤ 200 cm.

5.4.2 ARGISSOLOS VERMELHO-AMARELOS Distróficos espessarênicos

Soils with a sandy texture from the surface to a depth of > 100 cm and ≤ 200 cm.

5.4.3 ARGISSOLOS VERMELHO-AMARELOS Distróficos arênicos abrúpticos

Soils with an abrupt textural change and a sandy texture from the soil surface to a depth of ≥ 50 cm and ≤ 100 cm.

5.4.4 ARGISSOLOS VERMELHO-AMARELOS Distróficos arênicos

Soils with a sandy texture from the surface to a depth of ≥ 50 cm and ≤ 100 cm.

5.4.5 ARGISSOLOS VERMELHO-AMARELOS Distróficos abrúpticos

Soils with an abrupt textural change.

5.4.6 ARGISSOLOS VERMELHO-AMARELOS Distróficos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons, in a non-diagnostic position for Plintossolos Pétricos, all within 150 cm from the soil surface.

5.4.7 ARGISSOLOS VERMELHO-AMARELOS Distróficos plintossólicos

Soils with a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

5.4.8 ARGISSOLOS VERMELHO-AMARELOS Distróficos planossólicos

Soils with a planic qualifier within 150 cm from the soil surface.

5.4.9 ARGISSOLOS VERMELHO-AMARELOS Distróficos nitossólicos

Soils with a morphology (structure and clay films) similar to that of Nitossolos, differing from them in having a B/A textural ratio of > 1.5 and/or the presence of polychromy within 150 cm from the soil surface.

5.4.10 ARGISSOLOS VERMELHO-AMARELOS Distróficos latossólicos

Soils with a latosolic B horizon below the textural B horizon within 150 cm from the soil surface.

5.4.11 ARGISSOLOS VERMELHO-AMARELOS Distróficos típicos

Other soils that do not fit in the previous classes.

5.5 ARGISSOLOS VERMELHO-AMARELOS Eutróficos

5.5.1 ARGISSOLOS VERMELHO-AMARELOS Eutróficos leptofragmentários abrúpticos

Soils with an abrupt textural change and a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

5.5.2 ARGISSOLOS VERMELHO-AMARELOS Eutróficos lépticos abrúpticos

Soils with an abrupt textural change and a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

5.5.3 ARGISSOLOS VERMELHO-AMARELOS Eutróficos saprolíticos abrúpticos chernossólicos

Soils with an abrupt textural change, a chernozemic A horizon and clay activity ≥ 20 cmolc kg⁻¹ clay in most of the first 100 cm of the B horizon (including BA) and a Cr (soft) horizon and no fragmentary lithic or lithic contact, all within 100 cm from the soil surface (Oliveira; Prado, 1984, pp. 143-145, profile 1288).

5.5.4 ARGISSOLOS VERMELHO-AMARELOS Eutróficos abrúpticos plintossólicos

Soils with an abrupt textural change and a plinthic qualifier or plinthic horizon, in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

5.5.5 ARGISSOLOS VERMELHO-AMARELOS Eutróficos abrúpticos planossólicos

Soils with an abrupt textural change and a planic qualifier within 150 cm from the soil surface.

5.5.6 ARGISSOLOS VERMELHO-AMARELOS Eutróficos abrúpticos

Soils with an abrupt textural change.

5.5.7 ARGISSOLOS VERMELHO-AMARELOS Eutróficos luvissólicos

Soils with clay activity ≥ 20 cmolc kg⁻¹ clay and sum of bases ≥ 5.0 cmolc kg⁻¹, both in most of the first 100 cm of the B horizon (including BA) (Reunião..., 2017, profile RO-06).

5.5.8 ARGISSOLOS VERMELHO-AMARELOS Eutróficos planossólicos

Soils with a planic qualifier within 150 cm from the soil surface.

5.5.9 ARGISSOLOS VERMELHO-AMARELOS Eutróficos nitossólicos

Soils with a morphology (structure and clay films) similar to that of Nitossolos, differing from them in having a B/A textural ratio of > 1.5 and/or the presence of polychromy within 150 cm from the soil surface.

5.5.10 ARGISSOLOS VERMELHO-AMARELOS Eutróficos latossólicos

Soils with a latosolic B horizon below the textural B horizon within 150 cm from the soil surface.

5.5.11 ARGISSOLOS VERMELHO-AMARELOS Eutróficos típicos

Other soils that do not fit in the previous classes.

Notes

(30) Soils identified to date, on the plateaus of Rio Grande do Sul, Paraná, Santa Catarina and in the Pampas region of Rio Grande do Sul, under subtropical climate.

Chapter 6

Cambissolos

Cambissolos are soils composed of mineral material with an incipient B horizon underlying any type of surface horizon (except a histic horizon with a thickness of ≥ 40 cm) or a chernozemic A horizon, when high activity clay and high base saturation are observed in the incipient B. If any plinthite and/or petroplinthite, a gley or a vertic horizon are present, they do not meet the requirements for Plintossolos, Gleissolos or Vertissolos, respectively.

Classes of the 2nd categorical level (suborders)

1 CAMBISSOLOS HÍSTICOS

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Soils with a histic O horizon that does not meet the thickness criteria for Organossolos (Ghani; Rocha, 1997, profile 3; Reunião..., 2008, p. 165, profile 12).

2 CAMBISSOLOS HÚMICOS

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Soils with a humic A horizon.

3 CAMBISSOLOS FLÚVICOS

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Soils with a fluvic qualifier within 150 cm from the soil surface.

4 CAMBISSOLOS HÁPLICOS

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Other soils that do not fit in the previous classes.

Classes of the 3rd categorical level (great groups)

1 CAMBISSOLOS HÍSTICOS

1.1 CAMBISSOLOS HÍSTICOS Alumínicos

Soils with an aluminic qualifier in most of the first 100 cm of the B horizon (including BA) (Lemos, 1973, p. 330, profile 48).

1.2 CAMBISSOLOS HÍSTICOS Distróficos

Other soils with a base saturation of < 50% in most of the first 100 cm of the B horizon (including BA) (Reunião..., 2008, p. 165, profilefil 12).

2 CAMBISSOLOS HÚMICOS

2.1 CAMBISSOLOS HÚMICOS Aluminoférricos

Soils with an aluminic qualifier and Fe₂O₃ (by H₂SO₄) contents from 180 g kg⁻¹ to < 360 g kg⁻¹ soil, both in most of the first 100 cm of the B horizon (including BA).

2.2 CAMBISSOLOS HÚMICOS Alumínicos

Soils with an aluminic qualifier in most of the first 100 cm of the B horizon (including BA) (Lemos, 1973, p. 324, profile 47; Larach et al., 1984, v. 2, p. 629, profile 74; Reunião..., 2000, profile 16).

2.3 CAMBISSOLOS HÚMICOS Distroférricos

Soils with a base saturation of < 50% and Fe₂O₃ (by H₂SO₄) contents from 180 g kg⁻¹ to < 360 g kg⁻¹ soil, both in most of the first 100 cm of the B horizon (including BA).

2.4 CAMBISSOLOS HÚMICOS Distróficos

Other soils with a base saturation of < 50% in most of the first 100 cm of the B horizon (including BA).

3 CAMBISSOLOS FLÚVICOS

3.1 CAMBISSOLOS FLÚVICOS Carbonáticos

Soils with a carbonatic qualifier in one or more horizons or layers or with a calcic horizon, both within 150 cm from the soil surface

3.2 CAMBISSOLOS FLÚVICOS Sódicos

Soils with a sodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.3 CAMBISSOLOS FLÚVICOS Sálicos

Soils with a salic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.4 CAMBISSOLOS FLÚVICOS Alumínicos

Soils with an aluminic qualifier in most of the first 100 cm of the B horizon (including BA).

3.5 CAMBISSOLOS FLÚVICOS Ta Distróficos

Soils with high activity clay and a base saturation of < 50%, both in most of the first 100 cm of the B horizon (including BA).

3.6 CAMBISSOLOS FLÚVICOS Ta Eutróficos

Soils with high activity clay and a base saturation of ≥ 50%, both in most of the first 100 cm of the B horizon (including BA).

3.7 CAMBISSOLOS FLÚVICOS Tb Distróficos

Soils with low activity clay and a base saturation of < 50%, both in most of the first 100 cm of the B horizon (including BA).

3.8 CAMBISSOLOS FLÚVICOS Tb Eutróficos

Soils with low activity clay and a base saturation of ≥ 50%, both in most of the first 100 cm of the B horizon (including BA).

4 CAMBISSOLOS HÁPLICOS

4.1 CAMBISSOLOS HÁPLICOS Carbonáticos

Soils with a carbonatic qualifier in one or more horizons or layers or with a calcic horizon, both within 150 cm from the soil surface (Jacomine et al., 1977-1979, v. 2, pp. 773, 779 and 781, profiles 234, 237 and 238).

4.2 CAMBISSOLOS HÁPLICOS Sódicos

Soils with a sodic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

4.3 CAMBISSOLOS HÁPLICOS Perférricos

Soils with Fe₂O₃ (by H₂SO₄) contents of ≥ 360 g kg⁻¹ soil in most of the first 100 cm of the B horizon (including BA).

4.4 CAMBISSOLOS HÁPLICOS Ta Alumínicos

Soils with high activity clay and an aluminic qualifier in most of the first 100 cm of the B horizon (including BA).

4.5 CAMBISSOLOS HÁPLICOS Ta Distróficos

Soils with high activity clay and a base saturation of < 50%, both in most of the first 100 cm of the B horizon (including BA).

4.6 CAMBISSOLOS HÁPLICOS Ta Eutroférricos

Soils with high activity clay and a base saturation of ≥ 50% and Fe₂O₃ (by H₂SO₄) contents from 180 g kg⁻¹ to < 360 g kg⁻¹ soil, all in most of the first 100 cm of the B horizon (including BA).

4.7 CAMBISSOLOS HÁPLICOS Ta Eutróficos

Soils with high activity clay and a base saturation of ≥ 50%, both in most of the first 100 cm of the B horizon (including BA) (Projeto RADAMBRASIL, 1976, p. 254, profile 16).

4.8 CAMBISSOLOS HÁPLICOS Tb Alumínicos

Soils with low activity clay and an aluminic qualifier, both in most of the first 100 cm of the B horizon (including BA).

4.9 CAMBISSOLOS HÁPLICOS Tb Distroférricos

Soils with low activity clay and a base saturation of < 50% and Fe₂O₃ (by H₂SO₄) contents from 180 g kg⁻¹ to < 360 g kg⁻¹ soil, all in most of the first 100 cm of the B horizon (including BA) (Larach et al., 1984, v. 2, p. 633, profile 76).

4.10 CAMBISSOLOS HÁPLICOS Tb Distróficos

Soils with low activity clay and a base saturation of < 50%, both in most of the first 100 cm of the B horizon (including BA).

4.11 CAMBISSOLOS HÁPLICOS Tb Eutroférricos

Soils with low activity clay and a base saturation of ≥ 50% and Fe₂O₃ (by H₂SO₄) contents from 180 g kg⁻¹ to < 360 g kg⁻¹ soil, all in most of the first 100 cm of the B horizon (including BA).

4.12 CAMBISSOLOS HÁPLICOS Tb Eutróficos

Soils with low activity clay and a base saturation ≥ 50%, both in most of the first 100 cm of the B horizon (including BA) (Projeto RADAMBRASIL, 1976, p. 254, profile 16).

Classes of the 4th categorical level (subgroups)

1.1 CAMBISSOLOS HÍSTICOS Alumínicos

1.1.1 CAMBISSOLOS HÍSTICOS Alumínicos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

1.1.2 CAMBISSOLOS HÍSTICOS Alumínicos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

1.1.3 CAMBISSOLOS HÍSTICOS Alumínicos espodossólicos

Soils with a spodic qualifier within 150 cm from the soil surface.

1.1.4 CAMBISSOLOS HÍSTICOS Alumínicos típicos

Other soils that do not fit in the previous classes.

1.2 CAMBISSOLOS HÍSTICOS Distróficos

1.2.1 CAMBISSOLOS HÍSTICOS Distróficos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

1.2.2 CAMBISSOLOS HÍSTICOS Distróficos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

1.2.3 CAMBISSOLOS HÍSTICOS Distróficos espodossólicos

Soils with a spodic qualifier within 150 cm from the soil surface (Benites, 2001).

1.2.4 CAMBISSOLOS HÍSTICOS Distróficos típicos

Other soils that do not fit in the previous classes.

2.1 CAMBISSOLOS HÚMICOS Aluminoférricos

2.1.1 CAMBISSOLOS HÚMICOS Aluminoférricos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

2.1.2 CAMBISSOLOS HÚMICOS Aluminoférricos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

2.1.3 CAMBISSOLOS HÚMICOS Aluminoférricos espodossólicos

Soils with a spodic qualifier within 150 cm from the soil surface.

2.1.4 CAMBISSOLOS HÚMICOS Aluminoférricos latossólicos

Soils that have an incipient B horizon with morphological characteristics similar to those of a latosolic B but with a thickness or one or more physical, chemical or mineralogical characteristics that do not meet the requirements of a latosolic B horizon, within 150 cm from the soil surface.

2.1.5 CAMBISSOLOS HÚMICOS Aluminoférricos típicos

Other soils that do not fit in the previous classes.

2.2 CAMBISSOLOS HÚMICOS Alumínicos

2.2.1 CAMBISSOLOS HÚMICOS Alumínicos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

2.2.2 CAMBISSOLOS HÚMICOS Alumínicos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

2.2.3 CAMBISSOLOS HÚMICOS Alumínicos espodossólicos

Soils with a spodic qualifier within 150 cm from the soil surface.

2.2.4 CAMBISSOLOS HÚMICOS Alumínicos típicos

Other soils that do not fit in the previous classes.

2.3 CAMBISSOLOS HÚMICOS Distroférricos

2.3.1 CAMBISSOLOS HÚMICOS Distroférricos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

2.3.2 CAMBISSOLOS HÚMICOS Distroférricos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

2.3.3 CAMBISSOLOS HÚMICOS Distroférricos latossólicos

Soils that have an incipient B horizon with similar morphological characteristics to those of a latosolic B, but with a thickness or one or more physical, chemical or mineralogical characteristics that do not meet the requirements of a latosolic B horizon, within 150 cm from the soil surface.

2.3.4 CAMBISSOLOS HÚMICOS Distroférricos típicos

Other soils that do not fit in the previous classes.

2.4 CAMBISSOLOS HÚMICOS Distróficos

2.4.1 CAMBISSOLOS HÚMICOS Distróficos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

2.4.2 CAMBISSOLOS HÚMICOS Distróficos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

2.4.3 CAMBISSOLOS HÚMICOS Distróficos saprolíticos

Soils with a (soft) Cr horizon and no fragmentary lithic or lithic contact, all within 100 cm from the soil surface (Reunião..., 2008, profile 6).

2.4.4 CAMBISSOLOS HÚMICOS Distróficos latossólicos

Soils that have an incipient B horizon with similar morphological characteristics to those of a latosolic B, but with a thickness or one or more physical, chemical or mineralogical characteristics that do not meet the requirements of a latosolic B horizon, within 150 cm from the soil surface.

2.4.5 CAMBISSOLOS HÚMICOS Distróficos típicos

Other soils that do not fit in the previous classes.

3.1 CAMBISSOLOS FLÚVICOS Carbonáticos

3.1.1 CAMBISSOLOS FLÚVICOS Carbonáticos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.1.2 CAMBISSOLOS FLÚVICOS Carbonáticos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.1.3 CAMBISSOLOS FLÚVICOS Carbonáticos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

3.1.4 CAMBISSOLOS FLÚVICOS Carbonáticos típicos

Other soils that do not fit in the previous classes.

3.2 CAMBISSOLOS FLÚVICOS Sódicos

3.2.1 CAMBISSOLOS FLÚVICOS Sódicos salinos gleissólicos

Soils with a saline qualifier in one or more horizons or layers and a gley horizon in a non-diagnostic position for Gleissolos, both within 150 cm from the soil surface (Nascimento, 1998, profile 3).

3.2.2 CAMBISSOLOS FLÚVICOS Sódicos salinos

Soils with a saline qualifier in one or more horizons or layers, within 150 cm from the soil surface.

3.2.3 CAMBISSOLOS FLÚVICOS Sódicos típicos

Other soils that do not fit in the previous classes.

3.3 CAMBISSOLOS FLÚVICOS Sálicos

3.3.1 CAMBISSOLOS FLÚVICOS Sálicos gleissólicos

Soils with a gley horizon in a non-diagnostic position for Gleissolos, within 150 cm from the soil surface.

3.3.2 CAMBISSOLOS FLÚVICOS Sálicos típicos

Other soils that do not fit in the previous class.

3.4 CAMBISSOLOS FLÚVICOS Alumínicos

3.4.1 CAMBISSOLOS FLÚVICOS Alumínicos gleissólicos

Soils with a gley horizon in a non-diagnostic position for Gleissolos, within 150 cm from the soil surface.

3.4.2 CAMBISSOLOS FLÚVICOS Alumínicos típicos

Other soils that do not fit in the previous class.

3.5 CAMBISSOLOS FLÚVICOS Ta Distróficos

3.5.1 CAMBISSOLOS FLÚVICOS Ta Distróficos gleissólicos

Soils with a gley horizon in a non-diagnostic position for Gleissolos, within 150 cm from the soil surface.

3.5.2 CAMBISSOLOS FLÚVICOS Ta Distróficos típicos

Other soils that do not fit in the previous class.

3.6 CAMBISSOLOS FLÚVICOS Ta Eutróficos

3.6.1 CAMBISSOLOS FLÚVICOS Ta Eutróficos solódicos

Soils with a solodic qualifier in one or more horizons or layers, within 150 cm from the surface (Nascimento, 1998, profile 2).

3.6.2 CAMBISSOLOS FLÚVICOS Ta Eutróficos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

3.6.3 CAMBISSOLOS FLÚVICOS Ta Eutróficos gleissólicos

Soils with a gley horizon in a non-diagnostic position for Gleissolos, within 150 cm from the soil surface.

3.6.4 CAMBISSOLOS FLÚVICOS Ta Eutróficos planossólicos

Soils with a planic qualifier within 150 cm from the soil surface.

3.6.5 CAMBISSOLOS FLÚVICOS Ta Eutróficos típicos

Other soils that do not fit in the previous classes.

3.7 CAMBISSOLOS FLÚVICOS Tb Distróficos

3.7.1 CAMBISSOLOS FLÚVICOS Tb Distróficos gleissólicos

Soils with a gley horizon in a non-diagnostic position for Gleissolos, within 150 cm from the soil surface.

3.7.2 CAMBISSOLOS FLÚVICOS Tb Distróficos típicos

Other soils that do not fit in the previous class.

3.8 CAMBISSOLOS FLÚVICOS Tb Eutróficos

3.8.1 CAMBISSOLOS FLÚVICOS Tb Eutróficos gleissólicos

Soils with a gley horizon in a non-diagnostic position for Gleissolos, within 150 cm from the soil surface.

3.8.2 CAMBISSOLOS FLÚVICOS Tb Eutróficos típicos

Other soils that do not fit in the previous class.

4.1 CAMBISSOLOS HÁPLICOS Carbonáticos

4.1.1 CAMBISSOLOS HÁPLICOS Carbonáticos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.1.2 CAMBISSOLOS HÁPLICOS Carbonáticos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.1.3 CAMBISSOLOS HÁPLICOS Carbonáticos saprolíticos

Soils with a (soft) Cr horizon and no fragmentary lithic or lithic contact, within 100 cm from the soil surface.

4.1.4 CAMBISSOLOS HÁPLICOS Carbonáticos solódicos

Soils with a solodic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

4.1.5 CAMBISSOLOS HÁPLICOS Carbonáticos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

4.1.6 CAMBISSOLOS HÁPLICOS Carbonáticos típicos

Other soils that do not fit in the previous classes.

4.2 CAMBISSOLOS HÁPLICOS Sódicos

4.2.1 CAMBISSOLOS HÁPLICOS Sódicos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.2.2 CAMBISSOLOS HÁPLICOS Sódicos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.2.3 CAMBISSOLOS HÁPLICOS Sódicos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

4.2.4 CAMBISSOLOS HÁPLICOS Sódicos típicos

Other soils that do not fit in the previous classes.

4.3 CAMBISSOLOS HÁPLICOS Perférricos

4.3.1 CAMBISSOLOS HÁPLICOS Perférricos latossólicos

Soils that have an incipient B horizon with similar morphological characteristics to those of a latosolic B, but with a thickness or one or more physical, chemical or mineralogical characteristics that do not meet the requirements of a latosolic B horizon, within 150 cm from the soil surface.

4.3.2 CAMBISSOLOS HÁPLICOS Perférricos típicos

Other soils that do not fit in the previous class.

4.4 CAMBISSOLOS HÁPLICOS Ta Alumínicos

4.4.1 CAMBISSOLOS HÁPLICOS Ta Alumínicos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.4.2 CAMBISSOLOS HÁPLICOS Ta Alumínicos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.4.3 CAMBISSOLOS HÁPLICOS Ta Alumínicos gleissólicos

Soils with a gley horizon in a non-diagnostic position for Gleissolos, within 150 cm from the soil surface.

4.4.4 CAMBISSOLOS HÁPLICOS Ta Alumínicos típicos

Other soils that do not fit in the previous classes.

4.5 CAMBISSOLOS HÁPLICOS Ta Distróficos

4.5.1 CAMBISSOLOS HÁPLICOS Ta Distróficos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.5.2 CAMBISSOLOS HÁPLICOS Ta Distróficos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.5.3 CAMBISSOLOS HÁPLICOS Ta Distróficos típicos

Other soils that do not fit in the previous class.

4.6 CAMBISSOLOS HÁPLICOS Ta Eutroférricos

4.6.1 CAMBISSOLOS HÁPLICOS Ta Eutroférricos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.6.2 CAMBISSOLOS HÁPLICOS Ta Eutroférricos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.6.3 CAMBISSOLOS HÁPLICOS Ta Eutroférricos típicos

Other soils that do not fit in the previous class.

4.7 CAMBISSOLOS HÁPLICOS Ta Eutróficos

4.7.1 CAMBISSOLOS HÁPLICOS Ta Eutróficos fragmentários

Soils with a fragmentary lithic contact within 50 cm from the soil surface.

4.7.2 CAMBISSOLOS HÁPLICOS Ta Eutróficos líticos

Soils with a lithic contact within 50 cm from the soil surface.

4.7.3 CAMBISSOLOS HÁPLICOS Ta Eutróficos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.7.4 CAMBISSOLOS HÁPLICOS Ta Eutróficos lépticos hipocarbonáticos

Soils with a hypocarbonatic qualifier in one or more horizons or layers within 100 cm and with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface (Carvalho et al., 1979, pp. 779-780, profile BA-237, pp. 781-783, profile BA-238).

4.7.5 CAMBISSOLOS HÁPLICOS Ta Eutróficos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.7.6 CAMBISSOLOS HÁPLICOS Ta Eutróficos solódicos

Soils with a solodic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

4.7.7 CAMBISSOLOS HÁPLICOS Ta Eutróficos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

4.7.8 CAMBISSOLOS HÁPLICOS Ta Eutróficos argissólicos

Soils with an argiluvic qualifier within 150 cm from the soil surface.

4.7.9 CAMBISSOLOS HÁPLICOS Ta Eutróficos típicos

Other soils that do not fit in the previous classes.

4.8 CAMBISSOLOS HÁPLICOS Tb Alumínicos

4.8.1 CAMBISSOLOS HÁPLICOS Tb Alumínicos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.8.2 CAMBISSOLOS HÁPLICOS Tb Alumínicos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.8.3 CAMBISSOLOS HÁPLICOS Tb Alumínicos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons in a non-diagnostic position for Plintossolos Pétricos, all within 150 cm from the soil surface.

4.8.4 CAMBISSOLOS HÁPLICOS Tb Alumínicos plintossólicos

Soils with a plinthic qualifier or plinthic horizon in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

4.8.5 CAMBISSOLOS HÁPLICOS Tb Alumínicos espodossólicos

Soils with a spodic qualifier within 150 cm from the soil surface.

4.8.6 CAMBISSOLOS HÁPLICOS Tb Alumínicos típicos

Other soils that do not fit in the previous classes (Teske, 2010, profiles 1, 2, 7 e 8).

4.9 CAMBISSOLOS HÁPLICOS Tb Distroférricos

4.9.1 CAMBISSOLOS HÁPLICOS Tb Distroférricos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.9.2 CAMBISSOLOS HÁPLICOS Tb Distroférricos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.9.3 CAMBISSOLOS HÁPLICOS Tb Distroférricos típicos

Other soils that do not fit in the previous class.

4.10 CAMBISSOLOS HÁPLICOS Tb Distróficos

4.10.1 CAMBISSOLOS HÁPLICOS Tb Distróficos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.10.2 CAMBISSOLOS HÁPLICOS Tb Distróficos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.10.3 CAMBISSOLOS HÁPLICOS Tb Distróficos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons in a non-diagnostic position for Plintossolos Pétricos, all within 150 cm from the soil surface.

4.10.4 CAMBISSOLOS HÁPLICOS Tb Distróficos plintossólicos

Soils with a plinthic qualifier or plinthic horizon in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

4.10.5 CAMBISSOLOS HÁPLICOS Tb Distróficos argissólicos

Soils with an argiluvic qualifier within 150 cm from the soil surface.

4.10.6 CAMBISSOLOS HÁPLICOS Tb Distróficos latossólicos

Soils that have an incipient B horizon with morphological characteristics similar to those of a latosolic B, but with a thickness or one or more physical, chemical or mineralogical characteristics that do not meet the requirements of a latosolic B horizon, within 150 cm from the soil surface.

4.10.7 CAMBISSOLOS HÁPLICOS Tb Distróficos típicos

Other soils that do not fit in the previous classes.

4.11 CAMBISSOLOS HÁPLICOS Tb Eutroférricos

4.11.1 CAMBISSOLOS HÁPLICOS Tb Eutroférricos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.11.2 CAMBISSOLOS HÁPLICOS Tb Eutroférricos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.11.3 CAMBISSOLOS HÁPLICOS Tb Eutroférricos solódicos

Soils with a solodic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

4.11.4 CAMBISSOLOS HÁPLICOS Tb Eutroférricos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

4.11.5 CAMBISSOLOS HÁPLICOS Tb Eutroférricos gleissólicos

Soils with a gley horizon in a non-diagnostic position for Gleissolos, within 150 cm from the soil surface.

4.11.6 CAMBISSOLOS HÁPLICOS Tb Eutroférricos latossólicos

Soils that have an incipient B horizon with morphological characteristics similar to those of a latosolic B, but with a thickness or one or more physical, chemical or mineralogical characteristics that do not meet the requirements of a latosolic B horizon, within 150 cm from the soil surface.

4.11.7 CAMBISSOLOS HÁPLICOS Tb Eutroférricos típicos

Other soils that do not fit in the previous classes.

4.12 CAMBISSOLOS HÁPLICOS Tb Eutróficos

4.12.1 CAMBISSOLOS HÁPLICOS Tb Eutróficos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.12.2 CAMBISSOLOS HÁPLICOS Tb Eutróficos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.12.3 CAMBISSOLOS HÁPLICOS Tb Eutróficos solódicos plintossólicos

Soils with a plinthic qualifier or plinthic horizon in a non-diagnostic position for Plintossolos and with a solodic qualifier in one or more horizons or layers, all within 150 cm from the soil surface.

4.12.4 CAMBISSOLOS HÁPLICOS Tb Eutróficos planossólicos

Soils with a planic qualifier within 150 cm from the soil surface.

4.12.5 CAMBISSOLOS HÁPLICOS Tb Eutróficos latossólicos

Soils that have an incipient B horizon with morphological characteristics similar to those of a latosolic B, but with a thickness or one or more physical, chemical or mineralogical characteristics that do not meet the requirements of a latosolic B horizon, within 150 cm from the soil surface.

4.12.6 CAMBISSOLOS HÁPLICOS Tb Eutróficos chernossólicos

Soils with a chernozemic A horizon and clay activity ≥ 20 cmolc kg⁻¹ clay, in most of the first 100 cm of the B horizon (including BA).

4.12.7 CAMBISSOLOS HÁPLICOS Tb Eutróficos típicos

Other soils that do not fit in the previous classes.

Chapter 7

Chernossolos

Chernossolos are soils composed of mineral material and a chernozemic A horizon, followed by:

An incipient B or textural B horizon, both with high activity clay and high base saturation (≥ 50%) (excluding Vertissolos); or

A calcic or petrocalcic horizon or carbonatic qualifier coinciding with a chernozemic A and/or C horizon, possibly including a Bi horizon with a thickness of < 10 cm between the A and C horizons; or

A lithic contact, provided the chernozemic A horizon has a calcium carbonate equivalent content of ≥ 150 g kg⁻¹ soil .

Classes of the 2nd categorical level (suborders)

1 CHERNOSSOLOS RÊNDZICOS

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Soils with a chernozemic A horizon and:

A calcic, petrocalcic horizon or carbonatic qualifier coinciding with a chernozemic A and/or C horizon, possibly including a Bi horizon with a thickness of < 10 cm between the A and C horizons; or

A lithic contact, provided the chernozemic A horizon has a calcium carbonate equivalent content of ≥ 150 g kg⁻¹ soil.

2 CHERNOSSOLOS EBÂNICOS

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Soils with an ebanic qualifier in most of the first 100 cm of the B horizon (including BA).

3 CHERNOSSOLOS ARGILÚVICOS

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Soils with a textural B horizon below the chernozemic A horizon.

4 CHERNOSSOLOS HÁPLICOS

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Other soils that do not fit in the previous classes.

Classes of the 3rd categorical level (great groups)

1 CHERNOSSOLOS RÊNDZICOS

1.1 CHERNOSSOLOS RÊNDZICOS Petrocálcicos

Soils with a petrocalcic horizon within 150 cm from the soil surface (Reunião..., 2012, p. 102, profile 14).

1.2 CHERNOSSOLOS RÊNDZICOS Líticos

Soils with a fragmentary lithic or lithic contact within 50 cm from the soil surface (Jacomine et al., 1975b, p. 324, profile 73).

1.3 CHERNOSSOLOS RÊNDZICOS Órticos

Other soils that do not fit in the previous classes.

2 CHERNOSSOLOS EBÂNICOS

2.1 CHERNOSSOLOS EBÂNICOS Carbonáticos

Soils with a carbonatic qualifier in one or more horizons or layers or with a calcic horizon, both within 150 cm from the soil surface (Embrapa, 1980b, profile 01).

2.2 CHERNOSSOLOS EBÂNICOS Órticos

Other soils that do not fit in the previous class (Embrapa, 1980b, profile 06; Congresso..., 1991, p. 9, profile 6).

3 CHERNOSSOLOS ARGILÚVICOS

3.1 CHERNOSSOLOS ARGILÚVICOS Férricos

Soils with Fe₂O₃ (by H₂SO₄) contents ≥ 180 g kg⁻¹ soil in most of the first 100 cm of the B horizon (including BA) (Fasolo et al., 1980, p. 39, exam 31; Larach et al., 1984, p. 2, p. 560, profile 68).

3.2 CHERNOSSOLOS ARGILÚVICOS Carbonáticos

Soils with a carbonatic qualifier in one or more horizons or layers or with a calcic horizon, both within 150 cm from the soil surface.

3.3 CHERNOSSOLOS ARGILÚVICOS Órticos

Other soils that do not fit in the previous classes.

4 CHERNOSSOLOS HÁPLICOS

4.1 CHERNOSSOLOS HÁPLICOS Férricos

Soils with Fe₂O₃ (by H₂SO₄) contents ≥ 180 g kg⁻¹ soil in most of the first 100 cm of the B horizon (including BA).

4.2 CHERNOSSOLOS HÁPLICOS Carbonáticos

Soils with a carbonatic qualifier in one or more horizons or layers or with a calcic horizon, both within 150 cm from the soil surface.

4.3 CHERNOSSOLOS HÁPLICOS Órticos

Other soils that do not fit in the previous classes.

Classes of the 4th categorical level (subgroups)

1.1 CHERNOSSOLOS RÊNDZICOS Petrocálcicos

1.1.1 CHERNOSSOLOS RÊNDZICOS Petrocálcicos típicos

All the Chernossolos Rêndzicos Petrocálcicos (provisionally) (Reunião..., 2012, p. 102, profile 14).

1.2 CHERNOSSOLOS RÊNDZICOS Líticos

1.2.1 CHERNOSSOLOS RÊNDZICOS Líticos fragmentários

Soils with a fragmentary lithic contact.

1.2.2 CHERNOSSOLOS RÊNDZICOS Líticos típicos

Other soils that do not fit in the previous class (Jacomine et al., 1975b, p. 324, profile 73).

1.3 CHERNOSSOLOS RÊNDZICOS Órticos

1.3.1 CHERNOSSOLOS RÊNDZICOS Órticos saprolíticos

Soils with a (soft) Cr horizon and no fragmentary lithic or lithic contact, all within 100 cm from the soil surface (Reunião..., 1998, p. 53, profile 8).

1.3.2 CHERNOSSOLOS RÊNDZICOS Órticos típicos

Other soils that do not fit in the previous class.

2.1 CHERNOSSOLOS EBÂNICOS Carbonáticos

2.1.1 CHERNOSSOLOS EBÂNICOS Carbonáticos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface (Lemos, 1973, p. 263, profile 148).

2.1.2 CHERNOSSOLOS EBÂNICOS Carbonáticos típicos

Other soils that do not fit in the previous class (Sistema..., 1980).

2.2 CHERNOSSOLOS EBÂNICOS Órticos

2.2.1 CHERNOSSOLOS EBÂNICOS Órticos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface (Lemos, 1973, p. 280, profile 158).

2.2.2 CHERNOSSOLOS EBÂNICOS Órticos típicos

Other soils that do not fit in the previous class (Embrapa, 1980f).

3.1 CHERNOSSOLOS ARGILÚVICOS Férricos

3.1.1 CHERNOSSOLOS ARGILÚVICOS Férricos saprolíticos

Soils with a (soft) Cr horizon and no fragmentary lithic or lithic contact, all within 100 cm from the soil surface (Lemos, 1973, p. 191, profile 25).

3.1.2 CHERNOSSOLOS ARGILÚVICOS Férricos típicos

Other soils that do not fit in the previous class.

3.2 CHERNOSSOLOS ARGILÚVICOS Carbonáticos

3.2.1 CHERNOSSOLOS ARGILÚVICOS Carbonáticos saprolíticos

Soils with a (soft) Cr horizon and no fragmentary lithic or lithic contact, all within 100 cm from the soil surface.

3.2.2 CHERNOSSOLOS ARGILÚVICOS Carbonáticos abrúpticos

Soils with an abrupt textural change.

3.2.3 CHERNOSSOLOS ARGILÚVICOS Carbonáticos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

3.2.4 CHERNOSSOLOS ARGILÚVICOS Carbonáticos típicos

Other soils that do not fit in the previous classes.

3.3 CHERNOSSOLOS ARGILÚVICOS Órticos

3.3.1 CHERNOSSOLOS ARGILÚVICOS Órticos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.3.2 CHERNOSSOLOS ARGILÚVICOS Órticos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.3.3 CHERNOSSOLOS ARGILÚVICOS Órticos saprolíticos

Soils with a (soft) Cr horizon and no fragmentary lithic or lithic contact, all within 100 cm from the soil surface.

3.3.4 CHERNOSSOLOS ARGILÚVICOS Órticos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.3.5 CHERNOSSOLOS ARGILÚVICOS Órticos abrúpticos

Soils with an abrupt textural change.

3.3.6 CHERNOSSOLOS ARGILÚVICOS Órticos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

3.3.7 CHERNOSSOLOS ARGILÚVICOS Órticos epirredóxicos

Soils with a redoxic qualifier within 50 cm from the soil surface.

3.3.8 CHERNOSSOLOS ARGILÚVICOS Órticos endorredóxicos

Soils with a redoxic qualifier at a depth of > 50 cm and ≤ 150 cm from the soil surface.

3.3.9 CHERNOSSOLOS ARGILÚVICOS Órticos típicos

Other soils that do not fit in the previous classes.

4.1 CHERNOSSOLOS HÁPLICOS Férricos

4.1.1 CHERNOSSOLOS HÁPLICOS Férricos típicos

All the Chernossolos Háplicos Férricos (provisionally) (Larach et al., 1984, v. 2, p. 627, profile 73).

4.2 CHERNOSSOLOS HÁPLICOS Carbonáticos

4.2.1 CHERNOSSOLOS HÁPLICOS Carbonáticos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.2.2 CHERNOSSOLOS HÁPLICOS Carbonáticos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.2.3 CHERNOSSOLOS HÁPLICOS Carbonáticos saprolíticos

Soils with a (soft) Cr horizon and no fragmentary lithic or lithic contact, all within 100 cm from the soil surface.

4.2.4 CHERNOSSOLOS HÁPLICOS Carbonáticos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

4.2.5 CHERNOSSOLOS HÁPLICOS Carbonáticos típicos

Other soils that do not fit in the previous classes.

4.3 CHERNOSSOLOS HÁPLICOS Órticos

4.3.1 CHERNOSSOLOS HÁPLICOS Órticos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.3.2 CHERNOSSOLOS HÁPLICOS Órticos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.3.3 CHERNOSSOLOS HÁPLICOS Órticos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

4.3.4 CHERNOSSOLOS HÁPLICOS Órticos típicos

Other soils that do not fit in the previous classes.

Chapter 8

Espodossolos

Espodossolos are soils composed of mineral material and a spodic B horizon immediately below an E, A or a histic horizon within 200 cm from the soil surface or within 400 cm if the sum of the A+E horizons or the histic (< 40 cm) + E horizons exceeds a depth of 200 cm.

Classes of the 2nd categorical level (suborders)

1 ESPODOSSOLOS HUMILÚVICOS

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Soils with a spodic horizon identified, mainly, with the suffixes Bh and/or Bhm, isolated or overlying other types of horizons (spodic or non-spodic) (Jacomine et al., 1977-1979, v. 1, p. 734, profile 226).

2 ESPODOSSOLOS FERRILÚVICOS

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Soils with a spodic horizon identified, mainly, with the suffixes Bs and/or Bsm, isolated or overlying other types of horizons (spodic or non-spodic).

3 ESPODOSSOLOS FERRI-HUMILÚVICOS

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Other Espodossolos that do not fit in the previous classes.

Classes of the 3rd categorical level (great groups)

1 ESPODOSSOLOS HUMILÚVICOS

1.1 ESPODOSSOLOS HUMILÚVICOS Hidro-hiperespessos³¹

Soils with a spodic B horizon at a depth of > 200 cm and ≤ 400 cm; one or more horizons within 100 cm from the soil surface water-saturated for some time in most years (or are artificially drained) and have at least one of the following characteristics:

A histic H horizon; and/or

An Eg horizon or areas of manganese accumulation (due to reduction and oxidation) in the E or in the spodic B horizon, within 100 cm from the soil surface.

1.2 ESPODOSSOLOS HUMILÚVICOS Hidromórficos³¹

Soils that have a spodic B horizon at a depth of ≤ 200 cm from the soil surface; one or more horizons within 100 cm from the soil surface are water-saturated for some time in most years (or are artificially drained) and have at least one of the following characteristics:

A histic H horizon; and/or

An Eg horizon or areas of manganese accumulation (due to reduction and oxidation) in the E or in the spodic B horizon within 100 cm from the soil surface (Reunião..., 1979a, p. 213, profile 15).

1.3 ESPODOSSOLOS HUMILÚVICOS Hiperespessos

Soils with a spodic B horizon at a depth of > 200 cm and ≤ 400 cm from the soil surface.

1.4 ESPODOSSOLOS HUMILÚVICOS Órticos

Other soils that do not fit in the previous classes.

2 ESPODOSSOLOS FERRILÚVICOS

2.1 ESPODOSSOLOS FERRILÚVICOS Hidro-hiperespessos³²

Soils that have a spodic B horizon at a depth of > 200 cm and ≤ 400 cm; one or more horizons within 100 cm from the soil surface are water-saturated for some time in most years (or are artificially drained) and have at least one of the following characteristics:

A histic H horizon; and/or

Eg horizon or mottles or areas of manganese and/or iron oxide accumulation (due to manganese and/or iron reduction and oxidation) in the E or in the B spodic horizon, within 100 cm from the soil surface.

2.2 ESPODOSSOLOS FERRILÚVICOS Hidromórficos³²

Soils that have a spodic B horizon at a depth of ≤ 200 cm from the soil surface; one or more horizons within 100 cm from the soil surface are water-saturated for some time in most years (or are artificially drained) and have at least one of the following characteristics:

A histic H horizon; and/or

An Eg horizon or mottles or areas of manganese and/or iron oxide accumulation (due to manganese and/or iron reduction and oxidation) in the E or in the spodic B horizon, within 100 cm from the soil surface.

2.3 ESPODOSSOLOS FERRILÚVICOS Hiperespessos

Soils with a spodic B horizon at a depth > 200 cm and ≤ 400 cm from the soil surface.

2.4 ESPODOSSOLOS FERRILÚVICOS Órticos

Other soils that do not fit in the previous classes.

3 ESPODOSSOLOS FERRI-HUMILÚVICOS

3.1 ESPODOSSOLOS FERRI-HUMILÚVICOS Hidro-hiperespessos³³

Soils that have a spodic B horizon at a depth of > 200 cm and ≤ 400 cm; one or more horizons within 100 cm from the soil surface are water-saturated for some time in most years (or are artificially drained) and have at least one of the following characteristics:

A histic H horizon; and/or

An Eg horizon or mottles or areas of manganese and/or iron oxide accumulation (due to manganese and/or iron reduction and oxidation) in the E or in the B spodic horizon within 100 cm from the soil surface.

3.2 ESPODOSSOLOS FERRI-HUMILÚVICOS Hidromórficos³³

Soils that have a spodic B horizon at a depth of ≤ 200 cm from the soil surface; in one or more horizons within 100 cm from the soil surface are water-saturated for some time in most years (or are artificially drained) and have at least one of the following characteristics:

A histic H horizon; and/or

An Eg horizon or mottles or areas of manganese and/or iron oxide accumulation (due to manganese and or iron reduction and oxidation) in the E horizon or in the spodic B horizon, within 100 cm from the soil surface.

3.3 ESPODOSSOLOS FERRI-HUMILÚVICOS Hiperespessos

Soils with a spodic B horizon at a depth of > 200 cm and ≤ 400 cm from the soil surface.

3.4 ESPODOSSOLOS FERRI-HUMILÚVICOS Órticos

Other soils that do not fit in the previous classes.

Classes of the 4th categorical level (subgroups)

1.1 ESPODOSSOLOS HUMILÚVICOS Hidro-hiperespessos

1.1.1 ESPODOSSOLOS HUMILÚVICOS Hidro-hiperespessos organossólicos

Soils with a histic horizon that does not meet the thickness criteria for Organossolos.

1.1.2 ESPODOSSOLOS HUMILÚVICOS Hidro-hiperespessos típicos

Other soils that do not fit in the previous class.

1.2 ESPODOSSOLOS HUMILÚVICOS Hidromórficos

1.2.1 ESPODOSSOLOS HUMILÚVICOS Hidromórficos espessarênicos

Soils with a sandy texture from the surface to the upper part of the spodic B horizon, at a depth of > 100 cm and ≤ 200 cm from the soil surface.

1.2.2 ESPODOSSOLOS HUMILÚVICOS Hidromórficos arênicos

Soils with a sandy texture from the surface to the upper part of the spodic B horizon, at a depth of ≥ 50 cm and ≤100 cm (Reunião..., 1979a, p. 213, profile 15).

1.2.3 ESPODOSSOLOS HUMILÚVICOS Hidromórficos dúricos

Soils with a duric qualifier in one or more horizons within 150 cm from the soil surface.

1.2.4 ESPODOSSOLOS HUMILÚVICOS Hidromórficos organossólicos

Soils with a histic horizon that does not meet the thickness criteria for Organossolos.

1.2.5 ESPODOSSOLOS HUMILÚVICOS Hidromórficos típicos

Other soils that do not fit in the previous classes.

1.3 ESPODOSSOLOS HUMILÚVICOS Hiperespessos

1.3.1 ESPODOSSOLOS HUMILÚVICOS Hiperespessos típicos

All the Espodossolos Humilúvicos Hiperespessos (provisionally).

1.4 ESPODOSSOLOS HUMILÚVICOS Órticos

1.4.1 ESPODOSSOLOS HUMILÚVICOS Órticos espessarênicos

Soils with a sandy texture from the surface to the upper part of the spodic B horizon, which occurs at a depth of > 100 cm and ≤ 200 cm from the soil surface.

1.4.2 ESPODOSSOLOS HUMILÚVICOS Órticos arênicos

Soils with a sandy texture from the surface to the beginning of the spodic B horizon, which occurs at a depth of ≥ 50 cm and ≤100 cm.

1.4.3 ESPODOSSOLOS HUMILÚVICOS Órticos dúricos

Soils with a duric qualifier in one or more horizons within 150 cm from the soil surface.

1.4.4 ESPODOSSOLOS HUMILÚVICOS Órticos fragipânicos

Soils with a fragipan in one or more horizons within 150 cm from the soil surface.

1.4.5 ESPODOSSOLOS HUMILÚVICOS Órticos típicos

Other soils that do not fit in the previous classes.

2.1 ESPODOSSOLOS FERRILÚVICOS Hidro-hiperespessos

2.1.1 ESPODOSSOLOS FERRILÚVICOS Hidro-hiperespessos organossólicos

Soils with a histic horizon that does not meet the thickness criteria for Organossolos.

2.1.2 ESPODOSSOLOS FERRILÚVICOS Hidro-hiperespessos típicos

Other soils that do not fit in the previous class.

2.2 ESPODOSSOLOS FERRILÚVICOS Hidromórficos

2.2.1 ESPODOSSOLOS FERRILÚVICOS Hidromórficos espessarênicos

Soils with a sandy texture from the surface to the upper part of the spodic B horizon, which occurs at a depth of > 100 cm and ≤ 200 cm from the soil surface.

2.2.2 ESPODOSSOLOS FERRILÚVICOS Hidromórficos arênicos

Soils with a sandy texture from the surface to the upper part of the spodic B horizon, which occurs at a depth of ≥ 50 cm and ≤100 cm.

2.2.3 ESPODOSSOLOS FERRILÚVICOS Hidromórficos dúricos

Soils with a duric qualifier in one or more horizons within 150 cm from the soil surface.

2.2.4 ESPODOSSOLOS FERRILÚVICOS Hidromórficos organossólicos

Soils with a histic horizon that does not meet the thickness criteria for Organossolos.

2.2.5 ESPODOSSOLOS FERRILÚVICOS Hidromórficos típicos

Other soils that do not fit in the previous classes.

2.3 ESPODOSSOLOS FERRILÚVICOS Hiperespessos

2.3.1 ESPODOSSOLOS FERRILÚVICOS Hiperespessos típicos

All the Espodossolos Ferrilúvicos Hiperespessos (provisionally).

2.4 ESPODOSSOLOS FERRILÚVICOS Órticos

2.4.1 ESPODOSSOLOS FERRILÚVICOS Órticos espessarênicos

Soils with a sandy texture from the surface to the upper part of the spodic B horizon, which occurs at a depth of > 100 cm and ≤ 200 cm from the soil surface.

2.4.2 ESPODOSSOLOS FERRILÚVICOS Órticos arênicos

Soils with a sandy texture from the surface to the upper part of the spodic B horizon, which occurs at a depth of ≥ 50 cm and ≤100 cm.

2.4.3 ESPODOSSOLOS FERRILÚVICOS Órticos dúricos

Soils with a duric qualifier in one or more horizons within 150 cm from the soil surface.

2.4.4 ESPODOSSOLOS FERRILÚVICOS Órticos fragipânicos

Soils with a fragipan in one or more horizons within 150 cm from the soil surface.

2.4.5 ESPODOSSOLOS FERRILÚVICOS Órticos típicos

Other soils that do not fit in the previous classes.

3.1 ESPODOSSOLOS FERRI-HUMILÚVICOS Hidro-hiperespessos

3.1.1 ESPODOSSOLOS FERRI-HUMILÚVICOS Hidro-hiperespessos organossólicos

Soils with a histic horizon that does not meet the thickness criteria for Organossolos.

3.1.2 ESPODOSSOLOS FERRI-HUMILÚVICOS Hidro-hiperespessos típicos

Other soils that do not fit in the previous class.

3.2 ESPODOSSOLOS FERRI-HUMILÚVICOS Hidromórficos

3.2.1 ESPODOSSOLOS FERRI-HUMILÚVICOS Hidromórficos espessarênicos

Soils with a sandy texture from the surface to the upper part of the spodic B horizon, which occurs at a depth of > 100 cm and ≤ 200 cm from the soil surface.

3.2.2 ESPODOSSOLOS FERRI-HUMILÚVICOS Hidromórficos arênicos

Soils with a sandy texture from the surface to the upper part of the spodic B horizon, which occurs at a depth of ≥ 50 cm and ≤100 cm.

3.2.3 ESPODOSSOLOS FERRI-HUMILÚVICOS Hidromórficos dúricos

Soils with a duric qualifier in one or more horizons within 150 cm from the soil surface.

3.2.4 ESPODOSSOLOS FERRI-HUMILÚVICOS Hidromórficos organossólicos

Soils with a histic horizon that does not meet the thickness criteria for Organossolos.

3.2.5 ESPODOSSOLOS FERRI-HUMILÚVICOS Hidromórficos típicos

Other soils that do not fit in the previous classes.

3.3 ESPODOSSOLOS FERRI-HUMILÚVICOS Hiperespessos

3.3.1 ESPODOSSOLOS FERRI-HUMILÚVICOS Hiperespessos típicos

All the Espodossolos Ferri-humilúvicos Hiperespessos (provisionally).

3.4 ESPODOSSOLOS FERRI-HUMILÚVICOS Órticos

3.4.1 ESPODOSSOLOS FERRI-HUMILÚVICOS Órticos carbonáticos

Soils with a carbonatic qualifier in one or more horizons or layers or with a calcic horizon, both within 150 cm from the soil surface.

3.4.2 ESPODOSSOLOS FERRI-HUMILÚVICOS Órticos êutricos³⁴ arênicos

Soils with a eutric qualifier in most horizons within 100 cm from the soil surface and with a sandy texture from the surface to the upper part of the spodic B horizon, which occurs at a depth of ≥ 50 cm and ≤100 cm (Embrapa, 1987, p. 124, profile 15).

3.4.3 ESPODOSSOLOS FERRI-HUMILÚVICOS Órticos êutricos

Soils with a eutric qualifier in most horizons within 100 cm from the soil surface.

3.4.4 ESPODOSSOLOS FERRI-HUMILÚVICOS Órticos espessarênicos

Soils with a sandy texture from the surface to the upper part of the spodic B horizon, which occurs at a depth of > 100 cm and ≤ 200 cm from the soil surface.

3.4.5 ESPODOSSOLOS FERRI-HUMILÚVICOS Órticos arênicos

Soils with a sandy texture from the surface to the upper part of the spodic B horizon, which occurs at a depth of ≥ 50 cm and ≤100 cm (Embrapa, 1987, p. 151, profile 16).

3.4.6 ESPODOSSOLOS FERRI-HUMILÚVICOS Órticos dúricos

Soils with a duric qualifier in one or more horizons within 150 cm from the soil surface.

3.4.7 ESPODOSSOLOS FERRI-HUMILÚVICOS Órticos fragipânicos

Soils with a fragipan in one or more horizons within 150 cm from the soil surface.

3.4.8 ESPODOSSOLOS FERRI-HUMILÚVICOS Órticos típicos

Other soils that do not fit in the previous classes.

Notes

(31) The intention is to separate the poorly and very poorly drained soils of this class, which have a hydrophilic or hygrophilic primary vegetation.

(32) The intention is to separate the poorly and very poorly drained soils of this class, which have a hydrophilic or hygrophilic primary vegetation.

(33) The intention is to separate the poorly and very poorly drained soils of this class, which have a hydrophilic or hygrophilic primary vegetation.

(34) Parameter in test phase.

Chapter 9

Gleissolos

Gleissolos are soils composed of mineral material with a gley horizon starting within the first 50 cm from the soil surface, or at a depth > 50 cm and ≤ 150 cm provided that immediately below the A or E horizon or a histic horizon with insufficient thickness to define the class of Organossolos. They do not have a vertic horizon in a diagnostic position for Vertissolos or an exclusively sand or loamy sand texture in all horizons to a depth of 150 cm below the soil surface or down to a fragmentary lithic or lithic contact. A planic, plinthic, concretionary or lithoplinthic horizon, if present, must occur at a depth of > 200 cm from the soil surface.

Classes of the 2nd categorical level (suborders)

1 GLEISSOLOS TIOMÓRFICOS

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Soils with sulfidic materials in one or more horizons or layers or a sulfuric horizon, both within 100 cm from the soil surface.

2 GLEISSOLOS SÁLICOS

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Soils with a salic qualifier (EC ≥ 7 dS m⁻¹, at 25 °C) in one or more horizons or layers within 100 cm from the soil surface (Palmieri; Santos, 1980, p. 273, profile GB-45).

3 GLEISSOLOS MELÂNICOS

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Soils with a histic H horizon less than 40 cm thick or a chernozemic, prominent or humic A horizon.

4 GLEISSOLOS HÁPLICOS

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Other soils that do not fit in the previous classes.

Classes of the 3rd categorical level (great groups)

1 GLEISSOLOS TIOMÓRFICOS

1.1 GLEISSOLOS TIOMÓRFICOS Hísticos

Soils with a histic H horizon that does not meet the thickness criteria for Organossolos.

1.2 GLEISSOLOS TIOMÓRFICOS Órticos

Other soils that do not fit in the previous class.

2 GLEISSOLOS SÁLICOS

2.1 GLEISSOLOS SÁLICOS Sódicos

Soils with a sodic qualifier in one or more horizons or layers within 100 cm from the soil surface (Palmieri; Santos, 1980, p. 328, profile GB-57).

2.2 GLEISSOLOS SÁLICOS Órticos

Other soils that do not fit in the previous class.

3 GLEISSOLOS MELÂNICOS

3.1 GLEISSOLOS MELÂNICOS Carbonáticos

Soils with a carbonatic qualifier in one or more horizons or layers or with a calcic horizon, both within 100 cm from the soil surface.

3.2 GLEISSOLOS MELÂNICOS Sódicos

Soils with a sodic qualifier in one or more horizons or layers within 100 cm from the soil surface.

3.3 GLEISSOLOS MELÂNICOS Ta Alumínicos

Soils with high activity clay and an aluminic qualifier in most of the B and/or C horizons (including BA or CA), within 100 cm from the soil surface.

3.4 GLEISSOLOS MELÂNICOS T a Distróficos

Soils with high activity clay and a base saturation of < 50%, both in most of the B and/or C horizons (including BA or CA), within 100 cm from the soil surface.

3.5 GLEISSOLOS MELÂNICOS Ta Eutróficos

Soils with high activity clay and a base saturation of ≥ 50%, both in most of the B and/or C horizons (including BA or CA), within 100 cm from the soil surface.

3.6 GLEISSOLOS MELÂNICOS Tb Alumínicos

Soils with low activity clay and an aluminic qualifier in most of the B and/or C horizons (including BA or CA), within 100 cm from the soil surface.

3.7 GLEISSOLOS MELÂNICOS Tb Distróficos

Soils with low activity clay and a base saturation of < 50%, both in most of the B and/or C horizons (including BA or CA), within 100 cm from the soil surface.

3.8 GLEISSOLOS MELÂNICOS Tb Eutróficos

Soils with low activity clay and a base saturation of ≥ 50%, both in most of the B and/or C horizons (including BA or CA), within 100 cm from the soil surface (Lemos, 1973, p. 385, profile 75).

4 GLEISSOLOS HÁPLICOS

4.1 GLEISSOLOS HÁPLICOS Carbonáticos

Soils with a carbonatic qualifier in one or more horizons or layers or with a calcic horizon, both within 100 cm from the soil surface.

4.2 GLEISSOLOS HÁPLICOS Sódicos

Soils with a sodic qualifier in one or more horizons or layers within 100 cm from the soil surface.

4.3 GLEISSOLOS HÁPLICOS Ta Alumínicos

Soils with high activity clay and an aluminic qualifier in most of the B and/or C horizons (including BA or CA), within 100 cm from the soil surface.

4.4 GLEISSOLOS HÁPLICOS Ta Distróficos

Soils with high activity clay and a base saturation of < 50%, both in most of the B and/or C horizons (including BA or CA), within 100 cm from the soil surface.

4.5 GLEISSOLOS HÁPLICOS Ta Eutróficos

Soils with high activity clay and a base saturation of ≥ 50%, both in most of the B and/or C horizons (including BA or CA), within 100 cm from the soil surface.

4.6 GLEISSOLOS HÁPLICOS Tb Alumínicos

Soils with low activity clay and aluminic qualifier in most of the B and/or C horizons (including BA or CA), within 100 cm from the soil surface.

4.7 GLEISSOLOS HÁPLICOS Tb Distróficos

Soils with low activity clay and a base saturation of < 50%, both in most of the B and/or C horizons (including BA or CA), within 100 cm from the soil surface.

4.8 GLEISSOLOS HÁPLICOS Tb Eutróficos

Soils with low activity clay and a base saturation of ≥ 50%, both in most of the B and/or C horizons (including BA or CA), within 100 cm from the soil surface.

Classes of the 4th categorical level (subgroups)

1.1 GLEISSOLOS TIOMÓRFICOS Hísticos

1.1.1 GLEISSOLOS TIOMÓRFICOS Hísticos sódicos

Soils with a sodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

1.1.2 GLEISSOLOS TIOMÓRFICOS Hísticos sálicos

Soils with a salic qualifier in one or more horizons or layers within 150 cm from the soil surface.

1.1.3 GLEISSOLOS TIOMÓRFICOS Hísticos salinos

Soils with a saline qualifier in one or more horizons or layers within 150 cm from the soil surface (Reunião..., 1995, p. 42, profile 8-ES).

1.1.4 GLEISSOLOS TIOMÓRFICOS Hísticos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

1.1.5 GLEISSOLOS TIOMÓRFICOS Hísticos típicos

Other soils that do not fit in the previous classes.

1.2 GLEISSOLOS TIOMÓRFICOS Órticos

1.2.1 GLEISSOLOS TIOMÓRFICOS Órticos sódicos

Soils with a sodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

1.2.2 GLEISSOLOS TIOMÓRFICOS Órticos sálicos solódicos

Soils with salic and solodic qualifiers in one or more horizons or layers within 150 cm from the soil surface (Palmieri; Santos, 1980, p. 269, profile GB-44).

1.2.3 GLEISSOLOS TIOMÓRFICOS Órticos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

1.2.4 GLEISSOLOS TIOMÓRFICOS Órticos típicos

Other soils that do not fit in the previous classes.

2.1 GLEISSOLOS SÁLICOS Sódicos

2.1.1 GLEISSOLOS SÁLICOS Sódicos tiônicos

Soils with a sulfuric horizon or sulfidic materials at depths of > 100 cm and ≤ 150 cm from the soil surface.

2.1.2 GLEISSOLOS SÁLICOS Sódicos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface (Romero et al., 2009, profile 7).

2.1.3 GLEISSOLOS SÁLICOS Sódicos planossólicos

Soils with a planic qualifier within 150 cm from the soil surface.

2.1.4 GLEISSOLOS SÁLICOS Sódicos argissólicos

Soils with a textural B horizon (without abrupt textural change) or incipient B horizon with an argiluvic qualifier, within 150 cm from the soil surface.

2.1.5 GLEISSOLOS SÁLICOS Sódicos típicos

Other soils that do not fit in the previous classes (Reunião..., 1979a, p. 231, profile 18).

2.2 GLEISSOLOS SÁLICOS Órticos

2.2.1 GLEISSOLOS SÁLICOS Órticos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

2.2.2 GLEISSOLOS SÁLICOS Órticos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

2.2.3 GLEISSOLOS SÁLICOS Órticos típicos

Other soils that do not fit in the previous classes.

3.1 GLEISSOLOS MELÂNICOS Carbonáticos

3.1.1 GLEISSOLOS MELÂNICOS Carbonáticos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.1.2 GLEISSOLOS MELÂNICOS Carbonáticos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.1.3 GLEISSOLOS MELÂNICOS Carbonáticos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.1.4 GLEISSOLOS MELÂNICOS Carbonáticos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

3.1.5 GLEISSOLOS MELÂNICOS Carbonáticos cambissólicos

Soils with an incipient B horizon coinciding with a gley horizon within 150 cm from the soil surface.

3.1.6 GLEISSOLOS MELÂNICOS Carbonáticos neofluvissólicos

Soils that have a fluvic qualifier expressed by the presence of ≥ 4 stratified layers within 100 cm from the soil surface, which differ mainly in particle size.

3.1.7 GLEISSOLOS MELÂNICOS Carbonáticos típicos

Other soils that do not fit in the previous classes (Freitas et al., 1971, p. 61, profile 63).

3.2 GLEISSOLOS MELÂNICOS Sódicos

3.2.1 GLEISSOLOS MELÂNICOS Sódicos salinos

Soils with a saline qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.2.2 GLEISSOLOS MELÂNICOS Sódicos neofluvissólicos

Soils that have a fluvic qualifier expressed by the presence of ≥ 4 stratified layers within 100 cm from the soil surface, which differ mainly in particle size.

3.2.3 GLEISSOLOS MELÂNICOS Sódicos organossólicos

Soils with a histic horizon that does not meet the thickness criteria for Organossolos.

3.2.4 GLEISSOLOS MELÂNICOS Sódicos típicos

Other soils that do not fit in the previous classes.

3.3 GLEISSOLOS MELÂNICOS Ta alumínicos

3.3.1 GLEISSOLOS MELÂNICOS Ta Alumínicos tiônicos

Soils with a sulfuric horizon or sulfidic materials at depths of > 100 cm and ≤ 150 cm from the soil surface (Palmieri; Santos, 1980, p. 255, profile GB-41).

3.3.2 GLEISSOLOS MELÂNICOS Ta Alumínicos cambissólicos

Soils with an incipient B horizon coinciding with a gley horizon within 150 cm from the soil surface.

3.3.3 GLEISSOLOS MELÂNICOS Ta Alumínicos neofluvissólicos

Soils that have a fluvic qualifier expressed by the presence of ≥ 4 stratified layers within 100 cm from the soil surface, which differ mainly in particle size.

3.3.4 GLEISSOLOS MELÂNICOS Ta Alumínicos organossólicos

Soils with a histic horizon that does not meet the thickness criteria for Organossolos.

3.3.5 GLEISSOLOS MELÂNICOS Ta Alumínicos húmicos

Soils with a humic A horizon.

3.3.6 GLEISSOLOS MELÂNICOS Ta Alumínicos típicos

Other soils that do not fit in the previous classes.

3.4 GLEISSOLOS MELÂNICOS Ta Distróficos

3.4.1 GLEISSOLOS MELÂNICOS Ta Distróficos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.4.2 GLEISSOLOS MELÂNICOS Ta Distróficos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.4.3 GLEISSOLOS MELÂNICOS Ta Distróficos tiônicos

Soils with a sulfuric horizon or sulfidic materials at depths of > 100 cm and ≤ 150 cm from the soil surface.

3.4.4 GLEISSOLOS MELÂNICOS Ta Distróficos plintossólicos

Soils with a plinthic qualifier within 150 cm from the soil surface.

3.4.5 GLEISSOLOS MELÂNICOS Ta Distróficos cambissólicos

Soils with an incipient B horizon coinciding with a gley horizon within 150 cm from the soil surface.

3.4.6 GLEISSOLOS MELÂNICOS Ta Distróficos neofluvissólicos

Soils that have a fluvic qualifier expressed by the presence of ≥ 4 stratified layers within 100 cm from the soil surface, which differ mainly in particle size.

3.4.7 GLEISSOLOS MELÂNICOS Ta Distróficos organossólicos

Soils with a histic horizon that does not meet the thickness criteria for Organossolos.

3.4.8 GLEISSOLOS MELÂNICOS Ta Distróficos húmicos

Soils with a humic A horizon.

3.4.9 GLEISSOLOS MELÂNICOS Ta Distróficos típicos

Other soils that do not fit in the previous classes.

3.5 GLEISSOLOS MELÂNICOS Ta Eutróficos

3.5.1 GLEISSOLOS MELÂNICOS Ta Eutróficos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.5.2 GLEISSOLOS MELÂNICOS Ta Eutróficos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.5.3 GLEISSOLOS MELÂNICOS Ta Eutróficos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.5.4 GLEISSOLOS MELÂNICOS Ta Eutróficos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

3.5.5 GLEISSOLOS MELÂNICOS Ta Eutróficos luvissólicos

Soils with a textural B horizon coinciding with a gley horizon within 150 cm from the soil surface and without abrupt textural change.

3.5.6 GLEISSOLOS MELÂNICOS Ta Eutróficos cambissólicos

Soils with an incipient B horizon coinciding with a gley horizon within 150 cm from the soil surface.

3.5.7 GLEISSOLOS MELÂNICOS Ta Eutróficos neofluvissólicos

Soils that have a fluvic qualifier expressed by the presence of ≥ 4 stratified layers within 100 cm from the soil surface, which differ mainly in particle size.

3.5.8 GLEISSOLOS MELÂNICOS Ta Eutróficos organossólicos

Soils with a histic horizon that does not meet the thickness criteria for Organossolos.

3.5.9 GLEISSOLOS MELÂNICOS Ta Eutróficos chernossólicos

Soils with a chernozemic A horizon.

3.5.10 GLEISSOLOS MELÂNICOS Ta Eutróficos típicos

Other soils that do not fit in the previous classes.

3.6 GLEISSOLOS MELÂNICOS Tb Alumínicos

3.6.1 GLEISSOLOS MELÂNICOS Tb Alumínicos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface (Palmieri; Santos, 1980, p. 263, profile GB-29).

3.6.2 GLEISSOLOS MELÂNICOS Tb Alumínicos cambissólicos

Soils with an incipient B horizon coinciding with a gley horizon within 150 cm from the soil surface.

3.6.3 GLEISSOLOS MELÂNICOS Tb Alumínicos neofluvissólicos

Soils that have a fluvic qualifier expressed by the presence of ≥ 4 stratified layers within 100 cm from the soil surface, which differ mainly in particle size.

3.6.4 GLEISSOLOS MELÂNICOS Tb Alumínicos organossólicos

Soils with a histic horizon that does not meet the thickness criteria for Organossolos (Barros et al., 1958, p. 54, profile 16).

3.6.5 GLEISSOLOS MELÂNICOS Tb Alumínicos húmicos

Soils with a humic A horizon.

3.6.6 GLEISSOLOS MELÂNICOS Tb Alumínicos típicos

Other soils that do not fit in the previous classes.

3.7 GLEISSOLOS MELÂNICOS Tb Distróficos

3.7.1 GLEISSOLOS MELÂNICOS Tb Distróficos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers within 150 cm from the soil surface.

3.7.2 GLEISSOLOS MELÂNICOS Tb Distróficos plintossólicos

Soils with a plinthic qualifier within 150 cm from the soil surface.

3.7.3 GLEISSOLOS MELÂNICOS Tb Distróficos argissólicos

Soils with a textural B horizon (without abrupt textural change) or an incipient B horizon with an argiluvic qualifier within 150 cm from the soil surface.

3.7.4 GLEISSOLOS MELÂNICOS Tb Distróficos cambissólicos

Soils with an incipient B horizon coinciding with a gley horizon within 150 cm from the soil surface.

3.7.5 GLEISSOLOS MELÂNICOS Tb Distróficos neofluvissólicos

Soils that have a fluvic qualifier expressed by the presence of ≥ 4 stratified layers within 100 cm from the soil surface, which differ mainly in particle size.

3.7.6 GLEISSOLOS MELÂNICOS Tb Distróficos organossólicos

Soils with a histic horizon that does not meet the thickness criteria for Organossolos.

3.7.7 GLEISSOLOS MELÂNICOS Tb Distróficos húmicos

Soils with a humic A horizon.

3.7.8 GLEISSOLOS MELÂNICOS Tb Distróficos típicos

Other soils that do not fit in the previous classes.

3.8 GLEISSOLOS MELÂNICOS Tb Eutróficos

3.8.1 GLEISSOLOS MELÂNICOS Tb Eutróficos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.8.2 GLEISSOLOS MELÂNICOS Tb Eutróficos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.8.3 GLEISSOLOS MELÂNICOS Tb Eutróficos salinos

Soils with a saline qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.8.4 GLEISSOLOS MELÂNICOS Tb Eutróficos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.8.5 GLEISSOLOS MELÂNICOS Tb Eutróficos plintossólicos

Soils with a plinthic qualifier within 150 cm from the soil surface.

3.8.6 GLEISSOLOS MELÂNICOS Tb Eutróficos argissólicos

Soils with a textural B horizon (without abrupt textural change) or an incipient B horizon with an argiluvic qualifier, within 150 cm from the soil surface.

3.8.7 GLEISSOLOS MELÂNICOS Tb Eutróficos cambissólicos

Soils with an incipient B horizon coinciding with a gley horizon within 150 cm from the soil surface.

3.8.8 GLEISSOLOS MELÂNICOS Tb Eutróficos neofluvissólicos

Soils that have a fluvic qualifier expressed by the presence of ≥ 4 stratified layers within 100 cm from the soil surface, which differ mainly in particle size.

3.8.9 GLEISSOLOS MELÂNICOS Tb Eutróficos organossólicos

Soils with a histic horizon that does not meet the thickness criteria for Organossolos.

3.8.10 GLEISSOLOS MELÂNICOS Tb Eutróficos típicos

Other soils that do not fit in the previous classes.

4.1 GLEISSOLOS HÁPLICOS Carbonáticos

4.1.1 GLEISSOLOS HÁPLICOS Carbonáticos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.1.2 GLEISSOLOS HÁPLICOS Carbonáticos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.1.3 GLEISSOLOS HÁPLICOS Carbonáticos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

4.1.4 GLEISSOLOS HÁPLICOS Carbonáticos cambissólicos

Soils with an incipient B horizon coinciding with a gley horizon within 150 cm from the soil surface.

4.1.5 GLEISSOLOS HÁPLICOS Carbonáticos neofluvissólicos

Soils that have a fluvic qualifier expressed by the presence of ≥ 4 stratified layers within 100 cm from the soil surface, which differ mainly in particle size.

4.1.6 GLEISSOLOS HÁPLICOS Carbonáticos típicos

Other soils that do not fit in the previous classes.

4.2 GLEISSOLOS HÁPLICOS Sódicos

4.2.1 GLEISSOLOS HÁPLICOS Sódicos salinos

Soils with a saline qualifier in one or more horizons or layers within 150 cm from the soil surface (Carvalho Filho et al., 2003, extra profile Rio 273; Reunião..., 2012, p. 73, profile MS 9).

4.2.2 GLEISSOLOS HÁPLICOS Sódicos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

4.2.3 GLEISSOLOS HÁPLICOS Sódicos neofluvissólicos

Soils that have a fluvic qualifier expressed by the presence of ≥ 4 stratified layers within 100 cm from the soil surface, which differ mainly in particle size.

4.2.4 GLEISSOLOS HÁPLICOS Sódicos típicos

Other soils that do not fit in the previous classes.

4.3 GLEISSOLOS HÁPLICOS Ta Alumínicos

4.3.1 GLEISSOLOS HÁPLICOS Ta Alumínicos argissólicos

Soils with a textural B horizon (without abrupt textural change) or an incipient B horizon with an argiluvic qualifier, within 150 cm from the soil surface.

4.3.2 GLEISSOLOS HÁPLICOS Ta Alumínicos cambissólicos

Soils with an incipient B horizon coinciding with a gley horizon within 150 cm from the soil surface.

4.3.3 GLEISSOLOS HÁPLICOS Ta Alumínicos neofluvissólicos

Soils that have a fluvic qualifier expressed by the presence of ≥ 4 stratified layers within 100 cm from the soil surface, which differ mainly in particle size.

4.3.4 GLEISSOLOS HÁPLICOS Ta Alumínicos típicos

Other soils that do not fit in the previous classes.

4.4 GLEISSOLOS HÁPLICOS Ta Distróficos

4.4.1 GLEISSOLOS HÁPLICOS Ta Distróficos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.4.2 GLEISSOLOS HÁPLICOS Ta Distróficos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.4.3 GLEISSOLOS HÁPLICOS Ta Distróficos argissólicos

Soils with a textural B horizon (without abrupt textural change) or incipient B horizon with an argiluvic qualifier within 150 cm from the soil surface.

4.4.4 GLEISSOLOS HÁPLICOS Ta Distróficos cambissólicos

Soils with an incipient B horizon coinciding with the gley horizon, within 150 cm from the soil surface.

4.4.5 GLEISSOLOS HÁPLICOS Ta Distróficos neofluvissólicos

Soils that have a fluvic qualifier expressed by the presence of ≥ 4 stratified layers within 100 cm from the soil surface, which differ mainly in particle size.

4.4.6 GLEISSOLOS HÁPLICOS Ta Distróficos típicos

Other soils that do not fit in the previous classes.

4.5 GLEISSOLOS HÁPLICOS Ta Eutróficos

4.5.1 GLEISSOLOS HÁPLICOS Ta Eutróficos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.5.2 GLEISSOLOS HÁPLICOS Ta Eutróficos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.5.3 GLEISSOLOS HÁPLICOS Ta Eutróficos tiônicos

Soils with a sulfuric horizon or sulfidic materials at depths of > 100 cm and ≤ 150 cm from the soil surface.

4.5.4 GLEISSOLOS HÁPLICOS Ta Eutróficos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

4.5.5 GLEISSOLOS HÁPLICOS Ta Eutróficos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

4.5.6 GLEISSOLOS HÁPLICOS Ta Eutróficos luvissólicos

Soils with a textural B horizon coinciding with a gley horizon within 150 cm from the soil surface and with no abrupt textural change.

4.5.7 GLEISSOLOS HÁPLICOS Ta Eutróficos cambissólicos

Soils with an incipient B horizon coinciding with a gley horizon within 150 cm from the soil surface.

4.5.8 GLEISSOLOS HÁPLICOS Ta Eutróficos neofluvissólicos

Soils that have a fluvic qualifier expressed by the presence of ≥ 4 stratified layers within 100 cm from the soil surface, which differ mainly in particle size.

4.5.9 GLEISSOLOS HÁPLICOS Ta Eutróficos típicos

Other soils that do not fit in the previous classes.

4.6 GLEISSOLOS HÁPLICOS Tb Alumínicos

4.6.1 GLEISSOLOS HÁPLICOS Tb Alumínicos argissólicos

Soils with a textural B horizon (without abrupt textural change) or an incipient B horizon with an argiluvic qualifier within 150 cm from the soil surface.

4.6.2 GLEISSOLOS HÁPLICOS Tb Alumínicos cambissólicos

Soils with an incipient B horizon coinciding with a gley horizon within 150 cm from the soil surface.

4.6.3 GLEISSOLOS HÁPLICOS Tb Alumínicos neofluvissólicos

Soils that have a fluvic qualifier expressed by the presence of ≥ 4 stratified layers within 100 cm from the soil surface, which differ mainly in particle size.

4.6.4 GLEISSOLOS HÁPLICOS Tb Alumínicos típicos

Other soils that do not fit in the previous classes (Jacomine et al., 1975a, p. 357, profile 61; Reunião..., 1979a, p. 197, profile RJ-13).

4.7 GLEISSOLOS HÁPLICOS Tb Distróficos

4.7.1 GLEISSOLOS HÁPLICOS Tb Distróficos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.7.2 GLEISSOLOS HÁPLICOS Tb Distróficos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.7.3 GLEISSOLOS HÁPLICOS Tb Distróficos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers within 150 cm from the soil surface.

4.7.4 GLEISSOLOS HÁPLICOS Tb Distróficos plintossólicos

Soils with a plinthic qualifier within 150 cm from the soil surface.

4.7.5 GLEISSOLOS HÁPLICOS Tb Distróficos planossólicos

Soils with a planic qualifier within 150 cm from the soil surface (Reunião..., 2017, profile RO-07).

4.7.6 GLEISSOLOS HÁPLICOS Tb Distróficos argissólicos

Soils with a textural B horizon (without abrupt textural change) or an incipient B horizon with an argiluvic qualifier, within 150 cm from the soil surface.

4.7.7 GLEISSOLOS HÁPLICOS Tb Distróficos cambissólicos

Soils with an incipient B horizon coinciding with a gley horizon, within 150 cm from the soil surface.

4.7.8 GLEISSOLOS HÁPLICOS Tb Distróficos neofluvissólicos

Soils that have a fluvic qualifier expressed by the presence of ≥ 4 stratified layers within 100 cm from the soil surface, which differ mainly in particle size.

4.7.9 GLEISSOLOS HÁPLICOS Tb Distróficos típicos

Other soils that do not fit in the previous classes.

4.8 GLEISSOLOS HÁPLICOS Tb Eutróficos

4.8.1 GLEISSOLOS HÁPLICOS Tb Eutróficos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.8.2 GLEISSOLOS HÁPLICOS Tb Eutróficos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.8.3 GLEISSOLOS HÁPLICOS Tb Eutróficos salinos

Soils with a saline qualifier in one or more horizons or layers within 150 cm from the soil surface.

4.8.4 GLEISSOLOS HÁPLICOS Tb Eutróficos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

4.8.5 GLEISSOLOS HÁPLICOS Tb Eutróficos plintossólicos

Soils with a plinthic qualifier within 150 cm from the soil surface.

4.8.6 GLEISSOLOS HÁPLICOS Tb Eutróficos argissólicos

Soils with a textural B horizon (without abrupt textural change) or an incipient B horizon with an argiluvic qualifier, within 150 cm from the soil surface.

4.8.7 GLEISSOLOS HÁPLICOS Tb Eutróficos cambissólicos

Soils with an incipient B horizon coinciding with a gley horizon within 150 cm from the soil surface.

4.8.8 GLEISSOLOS HÁPLICOS Tb Eutróficos neofluvissólicos

Soils that have a fluvic qualifier expressed by the presence of ≥ 4 stratified layers within 100 cm from the soil surface, which differ mainly in particle size.

4.8.9 GLEISSOLOS HÁPLICOS Tb Eutróficos típicos

Other soils that do not fit in the previous classes.

Chapter 10

Latossolos

Latossolos are soils composed of mineral material and a latosolic B horizon preceded by any type of A horizon, within 200 cm from the soil surface or within 300 cm if the A horizon is more than 150 cm thick.

Classes of the 2nd categorical level (suborders)

1 LATOSSOLOS BRUNOS³⁵

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Soils with a retractable qualifier and a humic A horizon or organic carbon content > 10 g kg⁻¹ to a depth of ≤ 70 cm, which are brown in the uppermost part of the B horizon (including BA), predominantly with hue 7.5YR or yellower, simultaneously with value ≤ 4 and chroma ≤ 6 (moist color). Soils with hue 5YR in the uppermost part of the B horizon (including BA) are accepted, provided the value is ≤ 4 and the chroma is < 6 when moist.

2 LATOSSOLOS AMARELOS

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Soils with a hue of 7.5YR or yellower in most of the first 100 cm of the B horizon (including BA) that do not fit in the previous class.

3 LATOSSOLOS VERMELHOS

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Soils with a hue of 2.5YR or redder in most of the first 100 cm of the B horizon (including BA).

4 LATOSSOLOS VERMELHO-AMARELOS

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Other yellowish red and/or reddish yellow soils that do not fit in the previous classes.

Classes of the 3rd categorical level (great groups)

1 LATOSSOLOS BRUNOS

1.1 LATOSSOLOS BRUNOS Aluminoférricos

Soils with an aluminic qualifier and Fe₂O₃ (by H₂SO₄) contents from 180 g kg⁻¹ to < 360 g kg⁻¹ soil, both in most of the first 100 cm of the B horizon (including BA).

1.2 LATOSSOLOS BRUNOS Alumínicos

Soils with an aluminic qualifier in most of the first 100 cm of the B horizon (including BA).

1.3 LATOSSOLOS BRUNOS Distroférricos

Soils with a base saturation of < 50% and Fe₂O₃ (by H₂SO₄) contents from 180 g kg⁻¹ to < 360 g kg⁻¹ soil, both in most of the first 100 cm of the B horizon (including BA).

1.4 LATOSSOLOS BRUNOS Distróficos

Soils with a base saturation of < 50% in most of the first 100 cm of the B horizon (including BA).

2 LATOSSOLOS AMARELOS

2.1 LATOSSOLOS AMARELOS Acriférricos

Soils with an acric qualifier in one or more horizons within 150 cm from the soil surface and Fe₂O₃ (by H₂SO₄) contents from 180 g kg⁻¹ to < 360 g kg⁻¹ soil in most of the first 100 cm of the B horizon (including BA).

2.2 LATOSSOLOS AMARELOS Ácricos

Soils with an acric qualifier in one or more horizons within 150 cm from the soil surface.

2.3 LATOSSOLOS AMARELOS Alumínicos

Soils with an aluminic qualifier in most of the first 100 cm of the B horizon (including BA).

2.4 LATOSSOLOS AMARELOS Distroférricos

Soils with a base saturation of < 50% and Fe₂O₃ (by H₂SO₄) contents from 180 g kg⁻¹ to < 360 g kg⁻¹ soil, both in most of the first 100 cm of the B horizon (including BA).

2.5 LATOSSOLOS AMARELOS Distrocoesos

Soils with a base saturation of < 50% in most of the first 100 cm of the B horizon (including BA) and with a cohesive qualifier in one or more horizons, within 150 cm from the soil surface.

2.6 LATOSSOLOS AMARELOS Distróficos

Soils with a base saturation of < 50% in most of the first 100 cm of the B horizon (including BA).

2.7 LATOSSOLOS AMARELOS Eutróficos

Other soils with a base saturation of ≥ 50% in most of the first 100 cm of the B horizon (including BA).

3 LATOSSOLOS VERMELHOS

3.1 LATOSSOLOS VERMELHOS Perférricos

Soils with a Fe₂O₃ (by H₂SO₄) content ≥ 360 g kg⁻¹ soil in most of the first 100 cm of the B horizon (including BA).

3.2 LATOSSOLOS VERMELHOS Acriférricos

Soils with an acric qualifier in one or more horizons within 150 cm from the soil surface and Fe₂O₃ (by H₂SO₄) contents from 180 g kg⁻¹ to < 360 g kg⁻¹ soil in most of the first 100 cm of the B horizon (including BA) (Oliveira, 1999b, p. 67, profile IAC 1.447).

3.3 LATOSSOLOS VERMELHOS Ácricos

Soils with an acric qualifier in one or more horizons within 150 cm from the soil surface (Oliveira, 1999b, p. 57, profile IAC 1.457).

3.4 LATOSSOLOS VERMELHOS Aluminoférricos

Soils with an aluminic qualifier and Fe₂O₃ (by H₂SO₄) contents from 180 g kg⁻¹ to < 360 g kg⁻¹ soil, both in most of the first 100 cm of the B horizon (including BA).

3.5 LATOSSOLOS VERMELHOS Distroférricos

Soils with a base saturation of < 50% and Fe₂O₃ (by H₂SO₄) contents from 180 g kg⁻¹ to < 360 g kg⁻¹ soil, both in most of the first 100 cm of the B horizon (including BA).

3.6 LATOSSOLOS VERMELHOS Distróficos

Soils with a base saturation of < 50% in most of the first 100 cm of the B horizon (including BA).

3.7 LATOSSOLOS VERMELHOS Eutroférricos

Soils with a base saturation of ≥ 50% and Fe2O3 (by H2SO4) contents from 180 g kg⁻¹ to < 360 g kg⁻¹ soil, both in most of the first 100 cm of the B horizon (including BA) (Oliveira, 1999b, p. 63, profile IAC 1.360).

3.8 LATOSSOLOS VERMELHOS Eutróficos

Other soils with a base saturation of ≥ 50% in most of the first 100 cm of the B horizon (including BA) (Jacomine et al., 1973, v. 2, p. 81, profile 20).

4 LATOSSOLOS VERMELHO-AMARELOS

4.1 LATOSSOLOS VERMELHO-AMARELOS Acriférricos

Soils with an acric qualifier in one or more horizons within 150 cm from the soil surface and Fe₂O₃ (by H₂SO₄) contents from 180 g kg⁻¹ to < 360 g kg⁻¹ soil, in most of the first 100 cm of the B horizon (including BA).

4.2 LATOSSOLOS VERMELHO-AMARELOS Ácricos

Soils with an acric qualifier in one or more horizons within 150 cm from the soil surface.

4.3 LATOSSOLOS VERMELHO-AMARELOS Alumínicos

Soils with an aluminic qualifier in most of the first 100 cm of the B horizon (including BA).

4.4 LATOSSOLOS VERMELHO-AMARELOS Distroférricos

Soils with a base saturation of < 50% and Fe₂O₃ (by H₂SO₄) contents from 180 g kg⁻¹ to < 360 g kg⁻¹ soil, both in most of the first 100 cm of the B horizon (including BA).

4.5 LATOSSOLOS VERMELHO-AMARELOS Distróficos

Soils with a base saturation of < 50% in most of the first 100 cm of the B horizon (including BA).

4.6 LATOSSOLOS VERMELHO-AMARELOS Eutróficos

Other soils with a base saturation of ≥ 50% in most of the first 100 cm of the B horizon (including BA).

Classes of the 4th categorical level (subgroups)

1.1 LATOSSOLOS BRUNOS Aluminoférricos

1.1.1 LATOSSOLOS BRUNOS Aluminoférricos rúbricos

Soils with a rubric qualifier within the uppermost 100 cm of the B horizon (including BA).

1.1.2 LATOSSOLOS BRUNOS Aluminoférricos típicos

Other soils that do not fit in the previous class (Lemos, 1973, p. 53, profile RS-49).

1.2 LATOSSOLOS BRUNOS Alumínicos

1.2.1 LATOSSOLOS BRUNOS Alumínicos rúbricos

Soils with a rubric qualifier within the first 100 cm of the B horizon (including BA).

1.2.2 LATOSSOLOS BRUNOS Alumínicos típicos

Other soils that do not fit in the previous class (Lemos, 1973, p. 58, profile 27; Larach et al., 1984, v. 1, p. 333, complementary profile 39).

1.3 LATOSSOLOS BRUNOS Distroférricos

1.3.1 LATOSSOLOS BRUNOS Distroférricos rúbricos

Soils with a rubric qualifier within the first 100 cm of the B horizon (including BA).

1.3.2 LATOSSOLOS BRUNOS Distroférricos típicos

Other soils that do not fit in the previous class.

1.4 LATOSSOLOS BRUNOS Distróficos

1.4.1 LATOSSOLOS BRUNOS Distróficos rúbricos

Soils with a rubric qualifier within the first 100 cm of the B horizon (including BA).

1.4.2 LATOSSOLOS BRUNOS Distróficos espesso-húmicos

Soils with a humic A horizon and carbon contents ≥ 10 g kg⁻¹ to a depth of ≥ 80 cm.

1.4.3 LATOSSOLOS BRUNOS Distróficos húmicos

Soils with a humic A horizon.

1.4.4 LATOSSOLOS BRUNOS Distróficos típicos

Other soils that do not fit in the previous classes (Larach et al., 1984, v. 1, pp. 324, 327 and 334, profiles 37, 38 and complementary profile 40).

2.1 LATOSSOLOS AMARELOS Acriférricos

2.1.1 LATOSSOLOS AMARELOS Acriférricos espesso-húmicos

Soils with a humic A horizon and carbon contents ≥10 g kg⁻¹ to a depth of ≥ 80 cm.

2.1.2 LATOSSOLOS AMARELOS Acriférricos húmicos

Soils with a humic A horizon.

2.1.3 LATOSSOLOS AMARELOS Acriférricos típicos

Other soils that do not fit in the previous classes.

2.2 LATOSSOLOS AMARELOS Ácricos

2.2.1 LATOSSOLOS AMARELOS Ácricos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons in a non-diagnostic position for Plintossolos Pétricos, within 200 cm from the soil surface (Freitas et al., 1978, p. 190, profile 25).

2.2.2 LATOSSOLOS AMARELOS Ácricos plintossólicos

Soils with a plinthic qualifier or plinthic horizon in a non-diagnostic position for Plintossolos within 200 cm from the soil surface (Freitas et al., 1978, p. 230, profile 17).

2.2.3 LATOSSOLOS AMARELOS Ácricos espesso-húmicos

Soils with a humic A horizon and carbon contents ≥ 10 g kg⁻¹ to a depth of ≥ 80 cm.

2.2.4 LATOSSOLOS AMARELOS Ácricos húmicos

Soils with a humic A horizon (Projeto RADAMBRASIL, 1983, p. 421, profile 20).

2.2.5 LATOSSOLOS AMARELOS Ácricos típicos

Other soils that do not fit in the previous classes (Guia..., 1997, profile 3).

2.3 LATOSSOLOS AMARELOS Alumínicos

2.3.1 LATOSSOLOS AMARELOS Alumínicos argissólicos

Soils with a textural B/A ratio of ≥ 1.4, and/or having, in some part of the B horizon (excluding BA), a moderate blocky structure and few and weak clay films, within 200 cm from the soil surface.

2.3.2 LATOSSOLOS AMARELOS Alumínicos típicos

Other soils that do not fit in the previous class (Projeto RADAMBRASIL, 1977a, p. 206, profile 37; Projeto RADAMBRASIL 1977b, p. 168, profile 28).

2.4 LATOSSOLOS AMARELOS Distroférricos

2.4.1 LATOSSOLOS AMARELOS Distroférricos espesso-húmicos

Soils with a humic A horizon and carbon contents of ≥ 10 g kg⁻¹ to a depth of ≥ 80 cm.

2.4.2 LATOSSOLOS AMARELOS Distroférricos húmicos

Soils with a humic A horizon (Jacomine et al., 1977-1979, v. 1, p. 287, profile 57).

2.4.3 LATOSSOLOS AMARELOS Distroférricos típicos

Other soils that do not fit in the previous classes.

2.5 LATOSSOLOS AMARELOS Distrocoesos

2.5.1 LATOSSOLOS AMARELOS Distrocoesos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons in a non-diagnostic position for Plintossolos Pétricos, within 200 cm from the soil surface.

2.5.2 LATOSSOLOS AMARELOS Distrocoesos plintossólicos

Soils with a plinthic qualifier or plinthic horizon in a non-diagnostic position for Plintossolos within 200 cm from the soil surface.

2.5.3 LATOSSOLOS AMARELOS Distrocoesos argissólicos

Soils with a textural B/A ratio of ≥ 1.4, and/or having, in some part of the B horizon (excluding BA), a moderate blocky structure and few and weak clay films, within 200 cm from the soil surface.

2.5.4 LATOSSOLOS AMARELOS Distrocoesos antrópicos

Soils with an anthropic A horizon.

2.5.5 LATOSSOLOS AMARELOS Distrocoesos espesso-húmicos

Soils with a humic A horizon and carbon contents of ≥ 10 g kg⁻¹ to a depth of ≥ 80 cm.

2.5.6 LATOSSOLOS AMARELOS Distrocoesos húmicos

Soils with a humic A horizon.

2.5.7 LATOSSOLOS AMARELOS Distrocoesos típicos

Other soils that do not fit in the previous classes.

2.6 LATOSSOLOS AMARELOS Distróficos

2.6.1 LATOSSOLOS AMARELOS Distróficos psamíticos

Soils with a clay content of < 200 g kg⁻¹ in most of the first 150 cm from the soil surface.

2.6.2 LATOSSOLOS AMARELOS Distróficos petroplínticos plintossólicos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons, and with a plinthic qualifier or plinthic horizon, all in a non-diagnostic position for Plintossolos, within 200 cm from the soil surface (Reunião..., 2017, profile RO-14).

2.6.3 LATOSSOLOS AMARELOS Distróficos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons in a non-diagnostic position for Plintossolos Pétricos, within 200 cm from the soil surface.

2.6.4 LATOSSOLOS AMARELOS Distróficos plintossólicos

Soils with a plinthic qualifier or plinthic horizon in a non-diagnostic position for Plintossolos within 200 cm from the soil surface.

2.6.5 LATOSSOLOS AMARELOS Distróficos argissólicos

Soils with a textural B/A ratio of ≥ 1.4, and/or having, in some part of the B horizon (excluding BA), a moderate blocky structure and few and weak clay films, within 200 cm from the soil surface.

2.6.6 LATOSSOLOS AMARELOS Distróficos antrópicos

Soils with an anthropic A horizon.

2.6.7 LATOSSOLOS AMARELOS Distróficos espesso-húmicos

Soils with a humic A horizon and carbon contents of ≥ 10 g kg⁻¹ to a depth of ≥ 80 cm.

2.6.8 LATOSSOLOS AMARELOS Distróficos húmicos

Soils with a humic A horizon (Reunião..., 1979a, p. 113, profile PRJ 3).

2.6.9 LATOSSOLOS AMARELOS Distróficos típicos

Other soils that do not fit in the previous classes (Panoso, 1978, p. 130, profile 41).

2.7 LATOSSOLOS AMARELOS Eutróficos

2.7.1 LATOSSOLOS AMARELOS Eutróficos argissólicos

Soils with a textural B/A ratio of ≥ 1.4, and/or having, in some part of the B horizon (excluding BA), a moderate blocky structure and few and weak clay films, within 200 cm from the soil surface.

2.7.2 LATOSSOLOS AMARELOS Eutróficos típicos

Other soils that do not fit in the previous class (Panoso, 1978, p. 140, profile 81).

3.1 LATOSSOLOS VERMELHOS Perférricos

3.1.1 LATOSSOLOS VERMELHOS Perférricos cambissólicos

Soils with alterable primary materials that are visible³⁶ in the profile (to the naked eye or with a 10× lens) and/or with rock fragments in the B horizon at estimated percentages below the limits for an incipient B horizon, within 200 cm from the soil surface (excluding BC or B/C).

3.1.2 LATOSSOLOS VERMELHOS Perférricos espesso-húmicos

Soils with a humic A horizon and carbon contents of ≥ 10 g kg⁻¹ to a depth of ≥ 80 cm.

3.1.3 LATOSSOLOS VERMELHOS Perférricos húmicos

Soils with a humic A horizon (Projeto RADAMBRASIL, 1983, p. 415, profile 15).

3.1.4 LATOSSOLOS VERMELHOS Perférricos típicos

Other soils that do not fit in the previous classes (Congresso..., 1995, p. 37, profile XXV CBCS-6).

3.2 LATOSSOLOS VERMELHOS Acriférricos

3.2.1 LATOSSOLOS VERMELHOS Acriférricos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons in a non-diagnostic position for Plintossolos Pétricos within 200 cm from the soil surface (Oliveira, 1999b, p. 67, profile IAC 1.447).

3.2.2 LATOSSOLOS VERMELHOS Acriférricos espesso-húmicos

Soils with a humic A horizon and carbon content of ≥ 10 g kg⁻¹ to a depth of ≥ 80 cm.

3.2.3 LATOSSOLOS VERMELHOS Acriférricos húmicos

Soils with a humic A horizon.

3.2.4 LATOSSOLOS VERMELHOS Acriférricos típicos

Other soils that do not fit in the previous classes.

3.3 LATOSSOLOS VERMELHOS Ácricos

3.3.1 LATOSSOLOS VERMELHOS Ácricos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons in a non-diagnostic position for Plintossolos Pétricos, within 200 cm from the soil surface.

3.3.2 LATOSSOLOS VERMELHOS Ácricos espesso-húmicos

Soils with a humic A horizon and carbon content of ≥ 10 g kg⁻¹ to a depth of ≥ 80 cm.

3.3.3 LATOSSOLOS VERMELHOS Ácricos húmicos

Soils with a humic A horizon.

3.3.4 LATOSSOLOS VERMELHOS Ácricos típicos

Other soils that do not fit in the previous classes.

3.4 LATOSSOLOS VERMELHOS Aluminoférricos

3.4.1 LATOSSOLOS VERMELHOS Aluminoférricos retráticos

Soils with a retractable qualifier within the first 100 cm of the B horizon (including BA).

3.4.2 LATOSSOLOS VERMELHOS Aluminoférricos cambissólicos

Soils with alterable primary materials that are visible in the profile (to the naked eye or with a 10× lens) and/or with rock fragments in the B horizon at estimated percentages below the limits for an incipient B horizon, within 200 cm from the soil surface (excluding BC or B/C).

3.4.3 LATOSSOLOS VERMELHOS Aluminoférricos espesso-húmicos

Soils with a humic A horizon and carbon content of ≥10 g kg⁻¹ to a depth of ≥ 80 cm.

3.4.4 LATOSSOLOS VERMELHOS Aluminoférricos húmicos

Soils with a humic A horizon.

3.4.5 LATOSSOLOS VERMELHOS Aluminoférricos típicos

Other soils that do not fit in the previous classes (Lemos, 1973, p. 70, profile 16).

3.5 LATOSSOLOS VERMELHOS Distroférricos

3.5.1 LATOSSOLOS VERMELHOS Distroférricos retráticos

Soils with a retractable qualifier within the first 100 cm of the B horizon (including BA).

3.5.2 LATOSSOLOS VERMELHOS Distroférricos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons in a non-diagnostic position for Plintossolos Pétricos within 200 cm from the soil surface.

3.5.3 LATOSSOLOS VERMELHOS Distroférricos plintossólicos

Soils with a plinthic qualifier or plinthic horizon in a non-diagnostic position for Plintossolos within 200 cm from the soil surface.

3.5.4 LATOSSOLOS VERMELHOS Distroférricos cambissólicos

Soils with alterable primary materials that are visible in the profile (to the naked eye or with a 10× lens) and/or with rock fragments in the B horizon at estimated percentages below the limits for an incipient B horizon, within 200 cm from the soil surface (excluding BC or B/C).

3.5.5 LATOSSOLOS VERMELHOS Distroférricos espesso-húmicos

Soils with a humic A horizon and carbon content of ≥ 10 g kg⁻¹ to a depth of ≥ 80 cm.

3.5.6 LATOSSOLOS VERMELHOS Distroférricos húmicos

Soils with a humic A horizon.

3.5.7 LATOSSOLOS VERMELHOS Distroférricos típicos

Other soils that do not fit in the previous classes (Gomes et al., 1982, p. 210, profile 24).

3.6 LATOSSOLOS VERMELHOS Distróficos

3.6.1 LATOSSOLOS VERMELHOS Distróficos retráticos

Soils with a retractable qualifier within the first 100 cm of the B horizon (including BA) (Reunião..., 2008, profile 9).

3.6.2 LATOSSOLOS VERMELHOS Distróficos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons in a non-diagnostic position for Plintossolos Pétricos, within 200 cm from the soil surface.

3.6.3 LATOSSOLOS VERMELHOS Distróficos argissólicos

Soils with a textural B/A ratio of ≥ 1.4, and/or having, in some part of the B horizon (excluding BA), a moderate blocky structure and few and weak clay films, within 200 cm from the soil surface.

3.6.4 LATOSSOLOS VERMELHOS Distróficos cambissólicos

Soils with alterable primary materials that are visible in the profile (to the naked eye or with a 10× lens) and/or with rock fragments in the B horizon at estimated percentages below the limits for an incipient B horizon, within 200 cm from the soil surface (excluding BC or B/C).

3.6.5 LATOSSOLOS VERMELHOS Distróficos espesso-húmicos

Soils with a humic A horizon and carbon contents of ≥10 g kg⁻¹ to a depth of ≥ 80 cm.

3.6.6 LATOSSOLOS VERMELHOS Distróficos húmicos

Soils with a humic A horizon.

3.6.7 LATOSSOLOS VERMELHOS Distróficos típicos

Other soils that do not fit in the previous classes.

3.7 LATOSSOLOS VERMELHOS Eutroférricos

3.7.1 LATOSSOLOS VERMELHOS Eutroférricos cambissólicos

Soils with alterable primary materials that are visible in the profile (to the naked eye or with a 10× lens) and/or with rock fragments in the B horizon at estimated percentages below the limits for an incipient B horizon, within 200 cm from the soil surface (excluding BC or B/C).

3.7.2 LATOSSOLOS VERMELHOS Eutroférricos típicos

Other soils that do not fit in the previous class.

3.8 LATOSSOLOS VERMELHOS Eutróficos

3.8.1 LATOSSOLOS VERMELHOS Eutróficos argissólicos

Soils with a textural B/A ratio of ≥ 1.4, and/or having, in some part of the B horizon (excluding BA), a moderate blocky structure and few and weak clay films, within 200 cm from the soil surface.

3.8.2 LATOSSOLOS VERMELHOS Eutróficos cambissólicos

Soils with alterable primary materials that are visible in the profile (to the naked eye or with a 10× lens) and/or with rock fragments in the B horizon, at estimated percentages below the limits for an incipient B horizon, within 200 cm from the soil surface (excluding BC or B/C).

3.8.3 LATOSSOLOS VERMELHOS Eutróficos típicos

Other soils that do not fit in the previous classes.

4.1 LATOSSOLOS VERMELHO-AMARELOS Acriférricos

4.1.1 LATOSSOLOS VERMELHO-AMARELOS Acriférricos espesso-húmicos

Soils with a humic A horizon and carbon contents of ≥ 10 g kg⁻¹ to a depth of ≥ 80 cm.

4.1.2 LATOSSOLOS VERMELHO-AMARELOS Acriférricos húmicos

Soils with a humic A horizon.

4.1.3 LATOSSOLOS VERMELHO-AMARELOS Acriférricos típicos

Other soils that do not fit in the previous classes (Projeto RADAMBRASIL, 1983, p. 424, extra profile 1).

4.2 LATOSSOLOS VERMELHO-AMARELOS Ácricos

4.2.1 LATOSSOLOS VERMELHO-AMARELOS Ácricos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons in a non-diagnostic position for Plintossolos Pétricos, within 200 cm from the soil surface.

4.2.2 LATOSSOLOS VERMELHO-AMARELOS Ácricos espesso-húmicos

Soils with a humic A horizon and carbon contents of ≥10 g kg⁻¹ to a depth of ≥ 80 cm.

4.2.3 LATOSSOLOS VERMELHO-AMARELOS Ácricos húmicos

Soils with a humic A horizon.

4.2.4 LATOSSOLOS VERMELHO-AMARELOS Ácricos típicos

Other soils that do not fit in the previous classes (Reunião..., 1979a, p. 149, profile PRJ 7).

4.3 LATOSSOLOS VERMELHO-AMARELOS Alumínicos

4.3.1 LATOSSOLOS VERMELHO-AMARELOS Alumínicos argissólicos

Soils with a textural B/A ratio of ≥ 1.4, and/or having, in some part of the B horizon (excluding BA), a moderate blocky structure and few and weak clay films, within 200 cm from the soil surface.

4.3.2 LATOSSOLOS VERMELHO-AMARELOS Alumínicos típicos

Other soils that do not fit in the previous class (Projeto RADAMBRASIL, 1977a, p. 207, profile 58).

4.4 LATOSSOLOS VERMELHO-AMARELOS Distroférricos

4.4.1 LATOSSOLOS VERMELHO-AMARELOS Distroférricos argissólicos

Soils with a textural B/A ratio of ≥ 1.4, and/or having, in some part of the B horizon (excluding BA), a moderate blocky structure and few and weak clay films, within 200 cm from the soil surface.

4.4.2 LATOSSOLOS VERMELHO-AMARELOS Distroférricos cambissólicos

Soils with alterable primary materials that are visible in the profile (to the naked eye or with a 10× lens) and/or with rock fragments in the B horizon, at estimated percentages below the limits for an incipient B horizon, within 200 cm from the soil surface (excluding BC or B/C).

4.4.3 LATOSSOLOS VERMELHO-AMARELOS Distroférricos típicos

Other soils that do not fit in the previous classes (Jacomine et al., 1977-1979, v. 1, p. 295, profile 59).

4.5 LATOSSOLOS VERMELHO-AMARELOS Distróficos

4.5.1 LATOSSOLOS VERMELHO-AMARELOS Distróficos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons in a non-diagnostic position for Plintossolos Pétricos, within 200 cm from the soil surface.

4.5.2 LATOSSOLOS VERMELHO-AMARELOS Distróficos plintossólicos

Soils with a plinthic qualifier and/or plinthic horizon in a non-diagnostic position for Plintossolos within 200 cm from the soil surface.

4.5.3 LATOSSOLOS VERMELHO-AMARELOS Distróficos argissólicos

Soils with a textural B/A ratio of ≥ 1.4, and/or having, in some part of the B horizon (excluding BA), a moderate blocky structure and few and weak clay films, within 200 cm from the soil surface.

4.5.4 LATOSSOLOS VERMELHO-AMARELOS Distróficos cambissólicos

Soils with alterable primary materials that are visible in the profile (to the naked eye or with a 10× lens) and/or with rock fragments in the B horizon, at estimated percentages below the limits for an incipient B horizon, within 200 cm from the soil surface (excluding BC and B/C).

4.5.5 LATOSSOLOS VERMELHO-AMARELOS Distróficos espesso-húmicos

Soils with a humic A horizon and carbon content of ≥ 10 g kg⁻¹ to a depth of ≥ 80 cm.

4.5.6 LATOSSOLOS VERMELHO-AMARELOS Distróficos húmicos

Soils with a humic A horizon (Projeto RADAMBRASIL, 1983, p. 428, extra profile 56).

4.5.7 LATOSSOLOS VERMELHO-AMARELOS Distróficos típicos

Other soils that do not fit in the previous classes.

4.6 LATOSSOLOS VERMELHO-AMARELOS Eutróficos

4.6.1 LATOSSOLOS VERMELHO-AMARELOS Eutróficos argissólicos

Soils with a textural B/A ratio of ≥ 1.4, and/or having, in some part of the B horizon (excluding BA), a moderate blocky structure and few and weak clay films, within 200 cm from the soil surface.

4.6.2 LATOSSOLOS VERMELHO-AMARELOS Eutróficos cambissólicos

Soils with alterable primary materials that are visible in the profile (to the naked eye or with a 10× lens) and/or with rock fragments in the B horizon at estimated percentages below the limits for an incipient B horizon, within 200 cm from the soil surface (excluding BC and B/C).

4.6.3 LATOSSOLOS VERMELHO-AMARELOS Eutróficos típicos

Other soils that do not fit in the previous classes.

Notes

(35) Soils identified to date on the plateaus of Rio Grande do Sul, Santa Catarina and Paraná and in the region of Poços de Caldas, MG. The riteria are in the validation phase. The class of Latossolos Brunos Ácricos, of soils as those occurring in the municipalities of Guarapuava and Castro, PR, was excluded from the SiBCS.

(36) In the absence of mineralogical analysis, it is recommended to observe the presence of alterable primary materials (feldspar, biotite, muscovite etc.) in the profile with the naked eye, to use a 10× lens after crushing the dry soil material on a clear and clean surface and to estimate the percentage, using  a wire mesh or netting sieve.

Chapter 11

Luvissolos

Luvissolos are soils composed of mineral material and a textural B horizon with high activity clay and high base saturation in most of the first 100 cm of the B horizon (including BA), immediately below any type of A horizon (except a chernozemic A) or under an E horizon, and which meet the following requirement:

Plinthic, vertic or planic horizons, if present, do not meet the criteria for Plintossolos, Vertissolos or Planossolos, respectively, that is, they do not coincide with the uppermost part of the textural B horizon.

Classes of the 2nd categorical level (suborders)

1 LUVISSOLOS CRÔMICOS

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Soils with a chromic qualifier in most of the first 100 cm of the B horizon (including BA).

2 LUVISSOLOS HÁPLICOS

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Other soils that do not fit in the previous class.

Classes of the 3rd categorical level (great groups)

1 LUVISSOLOS CRÔMICOS

1.1 LUVISSOLOS CRÔMICOS Carbonáticos

Soils with a carbonatic qualifier in one or more horizons or layers or with a calcic horizon, both within 100 cm from the soil surface.

1.2 LUVISSOLOS CRÔMICOS Pálicos³⁷

Soils with a solum thickness (A + B, including E and excluding BC) of > 80 cm.

1.3 LUVISSOLOS CRÔMICOS Órticos

Other soils that do not fit in the previous classes.

2 LUVISSOLOS HÁPLICOS

2.1 LUVISSOLOS HÁPLICOS Pálicos³⁷

Soils with a solum thickness (A + B, including E and excluding BC) > 80 cm.

2.2 LUVISSOLOS HÁPLICOS Órticos

Other soils that do not fit in the previous class.

Classes of the 4th categorical level (subgroups)

1.1 LUVISSOLOS CRÔMICOS Carbonáticos

1.1.1 LUVISSOLOS CRÔMICOS Carbonáticos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers within 100 cm from the soil surface.

1.1.2 LUVISSOLOS CRÔMICOS Carbonáticos planossólicos

Soils with a planic qualifier within 100 cm from the soil surface.

1.1.3 LUVISSOLOS CRÔMICOS Carbonáticos típicos

Other soils that do not fit in the previous classes.

1.2 LUVISSOLOS CRÔMICOS Pálicos

1.2.1 LUVISSOLOS CRÔMICOS Pálicos saprolíticos

Soils with a (soft) Cr horizon and no fragmentary lithic or lithic contact, all within 100 cm from the soil surface (Jacomine et al., 1973, v. 2, pp. 275-277, profile 76).

1.2.2 LUVISSOLOS CRÔMICOS Pálicos arênicos

Soils with a sandy texture from the surface to a depth of ≥ 50 cm and ≤100 cm.

1.2.3 LUVISSOLOS CRÔMICOS Pálicos abrúpticos plintossólicos

Soils with an abrupt textural change and a plinthic qualifier or plinthic horizon in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

1.2.4 LUVISSOLOS CRÔMICOS Pálicos abrúpticos

Soils with an abrupt textural change.

1.2.5 LUVISSOLOS CRÔMICOS Pálicos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface (Reunião..., 2010a, profile AC 08).

1.2.6 LUVISSOLOS CRÔMICOS Pálicos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons in a non-diagnostic position for Plintossolos Pétricos, all within 150 cm from the soil surface.

1.2.7 LUVISSOLOS CRÔMICOS Pálicos planossólicos

Soils with a planic qualifier within 150 cm from the soil surface.

1.2.8 LUVISSOLOS CRÔMICOS Pálicos cambissólicos

Soils with ≥ 4% alterable primary materials visible in the profile (to the naked eye or with a 10× lens) and/or with ≥ 5% rock fragments in the B horizon (excluding BC and/or B/C), both within 150 cm from the soil surface.

1.2.9 LUVISSOLOS CRÔMICOS Pálicos típicos

Other soils that do not fit in the previous classes.

1.3 LUVISSOLOS CRÔMICOS Órticos

1.3.1 LUVISSOLOS CRÔMICOS Órticos fragmentários

Soils with a fragmentary lithic contact within 50 cm from the soil surface.

1.3.2 LUVISSOLOS CRÔMICOS Órticos líticos

Soils with a lithic contact within 50 cm from the soil surface.

1.3.3 LUVISSOLOS CRÔMICOS Órticos salinos

Soils with a saline qualifier in one or more horizons or layers within 100 cm from the soil surface.

1.3.4 LUVISSOLOS CRÔMICOS Órticos solódicos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic and a solodic qualifier in one or more horizons or layers, all within 100 cm from the soil surface (Jacomine et al., 1972-1973, profile 56).

1.3.5 LUVISSOLOS CRÔMICOS Órticos solódicos planossólicos

Soils with solodic and planic qualifiers within 100 cm from the soil surface (Jacomine et al., 1972-1973, profile 53).

1.3.6 LUVISSOLOS CRÔMICOS Órticos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 100 cm from the soil surface.

1.3.7 LUVISSOLOS CRÔMICOS Órticos vertissólicos planossólicos

Soils with a planic qualifier and a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier, all within 100 cm from the soil surface.

1.3.8 LUVISSOLOS CRÔMICOS Órticos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 100 cm from the soil surface.

1.3.9 LUVISSOLOS CRÔMICOS Órticos planossólicos

Soils with a planic qualifier within 100 cm from the soil surface (Jacomine et al., 1972-1973, profile 52).

1.3.10 LUVISSOLOS CRÔMICOS Órticos típicos

Other soils that do not fit in the previous classes.

2.1 LUVISSOLOS HÁPLICOS Pálicos

2.1.1 LUVISSOLOS HÁPLICOS Pálicos hipocarbonáticos

Soils with a hypocarbonatic qualifier in one or more horizons or layers within 150 cm from the soil surface (Reunião ..., 2000, profile 8).

2.1.2 LUVISSOLOS HÁPLICOS Pálicos solódicos plintossólicos

Soils with a plinthic qualifier or plinthic horizon in a non-diagnostic position for Plintossolos and with a solodic qualifier in one or more horizons or layers, all within 150 cm from the soil surface (Nascimento, 1998, profile 5).

2.1.3 LUVISSOLOS HÁPLICOS Pálicos abrúpticos plintossólicos

Soils with an abrupt textural change and a plinthic qualifier or plinthic horizon in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface (Silva, 2000, profile 2).

2.1.4 LUVISSOLOS HÁPLICOS Pálicos abrúpticos

Soils with an abrupt textural change.

2.1.5 LUVISSOLOS HÁPLICOS Pálicos fragipânicos plintossólicos

Soils with a fragipan and a plinthic qualifier in one or more horizons or layers or a plinthic horizon in a non-diagnostic position for Plintossolos, all within 150 cm from the soil surface (Lacerda, 2000, profile L-2-4).

2.1.6 LUVISSOLOS HÁPLICOS Pálicos gleissólicos

Soils with a gley horizon in a non-diagnostic position for Gleissolos within 150 cm from the soil surface.

2.1.7 LUVISSOLOS HÁPLICOS Pálicos plintossólicos

Soils with a plinthic qualifier or plinthic horizon in a non-diagnostic position for Plintossolos within 150 cm from the soil surface.

2.1.8 LUVISSOLOS HÁPLICOS Pálicos típicos

Other soils that do not fit in the previous classes.

2.2 LUVISSOLOS HÁPLICOS Órticos

2.2.1 LUVISSOLOS HÁPLICOS Órticos gleissólicos

Soils with a gley horizon in a non-diagnostic position for Gleissolos within 80 cm (solum thickness ) from the soil surface.

2.2.2 LUVISSOLOS HÁPLICOS Órticos planossólicos

Soils with a planic qualifier within 100 cm from the soil surface.

2.2.3 LUVISSOLOS HÁPLICOS Órticos típicos

Other soils that do not fit in the previous classes.

Notes

(37) Derived from pale = "excessive development".

Chapter 12

Neossolos

Neossolos are poorly developed soils, composed of mineral material or of organic material < 20 cm thick, having no type of diagnostic B horizon. Gley, plinthic, vertic and chernozemic A horizons, when present, do not fulfill the diagnostic conditions for the classes of Gleissolos, Plintossolos, Vertissolos and Chernossolos, respectively.

Classes of the 2nd categorical level (suborders)

1 NEOSSOLOS LITÓLICOS

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Soils with a fragmentary lithic or lithic contact within 50 cm from the surface, with an A or a histic horizon resting directly on the rock, on a C or Cr horizon or on material with ≥ 90% (by volume) coarse fragments (eg., quartz gravel bed) with a diameter of > 2 mm (gravel, pebbles and boulders). A B horizon in early formation, with a thickness that is not representative of any type of diagnostic B horizon, is acceptable.

2 NEOSSOLOS FLÚVICOS

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Soils derived from alluvial sediments with an A horizon resting on a C horizon or layer and with a fluvic qualifier within 150 cm from the soil surface. A Bi horizon less than 10 cm thick is acceptable. There is no pronounced gleying within 50 cm from the soil surface.

3 NEOSSOLOS REGOLÍTICOS

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Soils without fragmentary lithic or lithic contact within 50 cm from the surface, with a histic or A horizon overlying a C or Cr horizon. A B horizon in early formation, with a thickness that is not representative of any type of diagnostic B horizon, is acceptable.

In addition, they must meet at least one of the following requirements:

Contain ≥ 4% alterable primary minerals (less resistant to weathering) in the total sand fraction, but based on 100 g ADFE (air-dried fine earth fraction), in some horizon within 150 cm from the soil surface;

Contain ≥ 5% of the mass of the C or Cr horizon, to a depth of 150 cm, with fragments of partially weathered rock, saprolite or fragments formed from remains of the oriented rock structure (pseudomorphs) from which the soil originated.

4 NEOSSOLOS QUARTZARÊNICOS

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Other soils without fragmentary lithic or lithic contact within 50 cm from the surface, with a sequence of A-C horizons, but with a sand or loamy sand texture in all horizons to a depth of ≥ 150 cm from the soil surface or down to a fragmentary lithic or lithic contact. They are essentially quartzous, having ≥ 95% quartz, chalcedony and opal in the coarse sand and fine sand fractions, and practically no alterable primary minerals (little resistant to weathering).

Classes of the 3rd categorical level (great groups)

1 NEOSSOLOS LITÓLICOS

1.1 NEOSSOLOS LITÓLICOS Hísticos

Soils with a histic horizon that does not meet the thickness criteria for Organossolos (Ghani; Rocha, 1997, profile 4).

1.2 NEOSSOLOS LITÓLICOS Húmicos

Soils with a humic A horizon (Jacomine et al., 1980, p. 41, exam 15).

1.3 NEOSSOLOS LITÓLICOS Carbonáticos

Soils with a carbonatic qualifier in one or more horizons or layers or with a calcic horizon, both within 50 cm from the soil surface, with no chernozemic A horizon.

1.4 NEOSSOLOS LITÓLICOS Chernossólicos

Soils with a chernozemic A horizon and clay activity ≥ 20 cmolc kg⁻¹ clay in most of the C horizon (including CA) within 50 cm from the soil surface, with no carbonatic qualifier.

1.5 NEOSSOLOS LITÓLICOS Distróficos

Soils with a base saturation of < 50% in most of the first 50 cm from the soil surface (Lemos, 1973, p. 364, profile RS-78).

1.6 NEOSSOLOS LITÓLICOS Eutróficos

Soils with a base saturation of ≥ 50% in most of the first 50 cm from the soil surface (Lemos, 1973, p. 337, profile RS-38).

2 NEOSSOLOS FLÚVICOS

2.1 NEOSSOLOS FLÚVICOS Carbonáticos

Soils with a carbonatic qualifier in one or more horizons or layers or with a calcic horizon, both within 150 cm from the soil surface.

2.2 NEOSSOLOS FLÚVICOS Sódicos

Soils with a sodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

2.3 NEOSSOLOS FLÚVICOS Sálicos

Soils with a salic qualifier in one or more horizons or layers within 150 cm from the soil surface.

2.4 NEOSSOLOS FLÚVICOS Psamíticos

Soils with predominance of a sandy texture within 150 cm from the soil surface, whereas a loamy texture (sandy loam class) is acceptable.

2.5 NEOSSOLOS FLÚVICOS Ta Eutróficos

Soils with high activity clay and a base saturation of ≥ 50%, both in most of the C horizon or layer (including CA) within 150 cm from the soil surface.

2.6 NEOSSOLOS FLÚVICOS Tb Distróficos

Soils with low activity clay and a base saturation of < 50%, both in most of the C horizon or layer (including CA), within 150 cm from the soil surface.

2.7 NEOSSOLOS FLÚVICOS Tb Eutróficos

Soils with low activity clay and a base saturation of ≥ 50%, both in most of the C horizon or layer (including CA) within 150 cm from the soil surface.

3 NEOSSOLOS REGOLÍTICOS

3.1 NEOSSOLOS REGOLÍTICOS Psamíticos

Soils with predominance of a sandy texture within 150 cm from the soil surface, while a loamy texture (sandy loam class) is acceptable, and no saprolite (Cr and/or Cr/R horizon or layer) within 50 cm from the soil surface. These soils contain ≥ 4% alterable minerals in the total sand fraction, but based on the ADFE fraction. Light or whitish colors are typical of these soils.

3.2 NEOSSOLOS REGOLÍTICOS Húmicos

Soils with a humic A horizon.

3.3 NEOSSOLOS REGOLÍTICOS Distróficos

Soils with a base saturation of < 50% in most of the C horizon (including CA) within 150 cm from the soil surface.

3.4 NEOSSOLOS REGOLÍTICOS Eutróficos

Soils with a base saturation of ≥ 50% in most of the C horizon (including CA) within 150 cm from the soil surface.

4 NEOSSOLOS QUARTZARÊNICOS

4.1 NEOSSOLOS QUARTZARÊNICOS Hidromórficos

Soils with a high water table during most of the year, in most years, imperfectly or poorly drained, meeting one or more of the following requirements:

A histic H horizon; and/or

Permanent water saturation within 50 cm from the soil surface; and/or

Presence of a water table within 150 cm from the soil surface during the dry season; and/or

Presence of a water table within 50 cm from the soil surface for a period of time, in most years, unless artificially drained, and meeting one or more of the following requirements:

Zero chroma;

Hue of 10YR or redder with value (moist color) of ≥ 4 and chroma of 1;

Hue of 10YR or redder with chroma of ≤ 2 and mottles (or with accumulation of iron and/or manganese) resulting from iron and/or manganese reduction and oxidation;

Hue of 2.5Y or yellower, with chroma of ≤ 3 and mottles (or with areas of iron and/or manganese accumulation) resulting from the reduction and oxidation of these elements;

Hue of 2.5Y or yellower and chroma of ≤ 1;

Hues of 5GY, 5G, 5BG or 5B.

4.2 NEOSSOLOS QUARTZARÊNICOS Órticos

Other soils that do not fit in the previous classes.

Classes of the 4th categorical level (subgroups)

1.1 NEOSSOLOS LITÓLICOS Hísticos

1.1.1 NEOSSOLOS LITÓLICOS Hísticos típicos

All the Neossolos Litólicos Hísticos (provisionally) (Ghani; Rocha, 1997, profile 4).

1.2 NEOSSOLOS LITÓLICOS Húmicos

1.2.1 NEOSSOLOS LITÓLICOS Húmicos espodossólicos

Soils with a spodic qualifier within 50 cm from the soil surface or down to a fragmentary lithic or lithic contact.

1.2.2 NEOSSOLOS LITÓLICOS Húmicos típicos

Other soils that do not fit in the previous class.

1.3 NEOSSOLOS LITÓLICOS Carbonáticos

1.3.1 NEOSSOLOS LITÓLICOS Carbonáticos fragmentários

Soils with a fragmentary lithic contact.

1.3.2 NEOSSOLOS LITÓLICOS Carbonáticos típicos

Other soils that do not fit in the previous class.

1.4 NEOSSOLOS LITÓLICOS Chernossólicos

1.4.1 NEOSSOLOS LITÓLICOS Chernossólicos fragmentários

Soils with a fragmentary lithic contact.

1.4.2 NEOSSOLOS LITÓLICOS Chernossólicos típicos

Other soils that do not fit in the previous class.

1.5 NEOSSOLOS LITÓLICOS Distróficos

1.5.1 NEOSSOLOS LITÓLICOS Distróficos fragmentários

Soils with a fragmentary lithic contact.

1.5.2 NEOSSOLOS LITÓLICOS Distróficos típicos

Other soils that do not fit in the previous class.

1.6 NEOSSOLOS LITÓLICOS Eutróficos

1.6.1 NEOSSOLOS LITÓLICOS Eutróficos fragmentários

Soils with a fragmentary lithic contact.

1.6.2 NEOSSOLOS LITÓLICOS Eutróficos típicos

Other soils that do not fit in the previous class.

2.1 NEOSSOLOS FLÚVICOS Carbonáticos

2.1.1 NEOSSOLOS FLÚVICOS Carbonáticos típicos

All the Neossolos Flúvicos Carbonáticos (provisionally).

2.2 NEOSSOLOS FLÚVICOS Sódicos

2.2.1 NEOSSOLOS FLÚVICOS Sódicos sálicos

Soils with a salic qualifier in one or more horizons or layers within 150 cm from the soil surface.

2.2.2 NEOSSOLOS FLÚVICOS Sódicos salinos

Soils with a saline qualifier in one or more horizons or layers within 150 cm from the soil surface.

2.2.3 NEOSSOLOS FLÚVICOS Sódicos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

2.2.4 NEOSSOLOS FLÚVICOS Sódicos típicos

Other soils that do not fit in the previous classes.

2.3 NEOSSOLOS FLÚVICOS Sálicos

2.3.1 NEOSSOLOS FLÚVICOS Sálicos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

2.3.2 NEOSSOLOS FLÚVICOS Sálicos típicos

Other soils that do not fit in the previous class.

2.4 NEOSSOLOS FLÚVICOS Psamíticos

2.4.1 NEOSSOLOS FLÚVICOS Psamíticos êutricos

Soils with a eutric qualifier in most horizons and/or layers within 100 cm from the soil surface.

2.4.2 NEOSSOLOS FLÚVICOS Psamíticos gleissólicos

Soils with a gley horizon in a non-diagnostic position for Gleissolos within 150 cm from the soil surface.

2.4.3 NEOSSOLOS FLÚVICOS Psamíticos espodossólicos

Soils with a spodic qualifier within 150 cm from the soil surface.

2.4.4 NEOSSOLOS FLÚVICOS Psamíticos típicos

Other soils that do not fit in the previous classes.

2.5 NEOSSOLOS FLÚVICOS Ta Eutróficos

2.5.1 NEOSSOLOS FLÚVICOS Ta Eutróficos salinos

Soils with a saline qualifier in one or more horizons or layers within 150 cm from the soil surface.

2.5.2 NEOSSOLOS FLÚVICOS Ta Eutróficos hipocarbonáticos

Soils with a hypocarbonatic qualifier in one or more horizons or layers within 150 cm from the soil surface.

2.5.3 NEOSSOLOS FLÚVICOS Ta Eutróficos solódicos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic and a solodic qualifier in one or more horizons or layers, all within 150 cm from the soil surface.

2.5.4 NEOSSOLOS FLÚVICOS Ta Eutróficos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

2.5.5 NEOSSOLOS FLÚVICOS Ta Eutróficos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or with a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

2.5.6 NEOSSOLOS FLÚVICOS Ta Eutróficos gleissólicos

Soils with a gley horizon in a non-diagnostic position for Gleissolos within 150 cm from the soil surface.

2.5.7 NEOSSOLOS FLÚVICOS Ta Eutróficos típicos

Other soils that do not fit in the previous classes.

2.6 NEOSSOLOS FLÚVICOS Tb Distróficos

2.6.1 NEOSSOLOS FLÚVICOS Tb Distróficos gleissólicos

Soils with a gley horizon in a non-diagnostic position for Gleissolos within 150 cm from the soil surface (Jacomine et al., 1975a, p. 367, profile 63).

2.6.2 NEOSSOLOS FLÚVICOS Tb Distróficos típicos

Other soils that do not fit in the previous class.

2.7 NEOSSOLOS FLÚVICOS Tb Eutróficos

2.7.1 NEOSSOLOS FLÚVICOS Tb Eutróficos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

2.7.2 NEOSSOLOS FLÚVICOS Tb Eutróficos gleissólicos

Soils with a gley horizon in a non-diagnostic position for Gleissolos within 150 cm from the soil surface.

2.7.3 NEOSSOLOS FLÚVICOS Tb Eutróficos típicos

Other soils that do not fit in the previous classes.

3.1 NEOSSOLOS REGOLÍTICOS Psamíticos

3.1.1 NEOSSOLOS REGOLÍTICOS Psamíticos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.1.2 NEOSSOLOS REGOLÍTICOS Psamíticos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.1.3 NEOSSOLOS REGOLÍTICOS Psamíticos solódicos

Soils with a solodic qualifier in one or more horizons or layers, both within 150 cm from the soil surface.

3.1.4 NEOSSOLOS REGOLÍTICOS Psamíticos fragipânicos

Soils with a fragipan in one or more horizons or layers within 150 cm from the soil surface.

3.1.5 NEOSSOLOS REGOLÍTICOS Psamíticos típicos

Other soils that do not fit in the previous classes.

3.2 NEOSSOLOS REGOLÍTICOS Húmicos

3.2.1 NEOSSOLOS REGOLÍTICOS Húmicos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.2.2 NEOSSOLOS REGOLÍTICOS Húmicos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.2.3 NEOSSOLOS REGOLÍTICOS Húmicos típicos

Other soils that do not fit in the previous classes.

3.3 NEOSSOLOS REGOLÍTICOS Distróficos

3.3.1 NEOSSOLOS REGOLÍTICOS Distróficos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.3.2 NEOSSOLOS REGOLÍTICOS Distróficos lépticos fragipânicos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm and with a fragipan in one or more horizons or layers within 150 cm from the soil surface.

3.3.3 NEOSSOLOS REGOLÍTICOS Distróficos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.3.4 NEOSSOLOS REGOLÍTICOS Distróficos fragipânicos

Soils with a fragipan in one or more horizons or layers within 150 cm from the soil surface.

3.3.5 NEOSSOLOS REGOLÍTICOS Distróficos gleissólicos

Soils with a gley horizon in a non-diagnostic position for Gleissolos within 150 cm from the soil surface.

3.3.6 NEOSSOLOS REGOLÍTICOS Distróficos típicos

Other soils that do not fit in the previous classes.

3.4 NEOSSOLOS REGOLÍTICOS Eutróficos

3.4.1 NEOSSOLOS REGOLÍTICOS Eutróficos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.4.2 NEOSSOLOS REGOLÍTICOS Eutróficos lépticos solódicos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm and with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.4.3 NEOSSOLOS REGOLÍTICOS Eutróficos lépticos fragipânicos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface and with a fragipan in one or more horizons or layers within 150 cm from the soil surface.

3.4.4 NEOSSOLOS REGOLÍTICOS Eutróficos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.4.5 NEOSSOLOS REGOLÍTICOS Eutróficos solódicos fragipânicos

Soils with a solodic qualifier and fragipan in one or more horizons or layers, both within 150 cm from the soil surface.

3.4.6 NEOSSOLOS REGOLÍTICOS Eutróficos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.4.7 NEOSSOLOS REGOLÍTICOS Eutróficos fragipânicos

Soils with a fragipan in one or more horizons or layers within 150 cm from the soil surface.

3.4.8 NEOSSOLOS REGOLÍTICOS Eutróficos gleissólicos

Soils with a gley horizon in a non-diagnostic position for Gleissolos within 150 cm from the soil surface.

3.4.9 NEOSSOLOS REGOLÍTICOS Eutróficos típicos

Other soils that do not fit in the previous classes.

4.1 NEOSSOLOS QUARTZARÊNICOS Hidromórficos

4.1.1 NEOSSOLOS QUARTZARÊNICOS Hidromórficos plintossólicos

Soils with a plinthic qualifier or plinthic horizon in a non-diagnostic position for Plintossolos, within 150 cm from the soil surface.

4.1.2 NEOSSOLOS QUARTZARÊNICOS Hidromórficos espodossólicos

Soils with a spodic qualifier within 150 cm from the soil surface.

4.1.3 NEOSSOLOS QUARTZARÊNICOS Hidromórficos neofluvissólicos

Soils with a fluvic qualifier within 150 cm from the soil surface.

4.1.4 NEOSSOLOS QUARTZARÊNICOS Hidromórficos organossólicos

Soils with a histic horizon that does not meet the thickness criteria for Organossolos (Guia..., 1997, profile 8).

4.1.5 NEOSSOLOS QUARTZARÊNICOS Hidromórficos típicos

Other soils that do not fit in the previous classes.

4.2 NEOSSOLOS QUARTZARÊNICOS Órticos

4.2.1 NEOSSOLOS QUARTZARÊNICOS Órticos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.2.2 NEOSSOLOS QUARTZARÊNICOS Órticos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

4.2.3 NEOSSOLOS QUARTZARÊNICOS Órticos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

4.2.4 NEOSSOLOS QUARTZARÊNICOS Órticos êutricos³⁸

Soils with a eutric qualifier in most horizons and/or layers within 100 cm from the soil surface.

4.2.5 NEOSSOLOS QUARTZARÊNICOS Órticos fragipânicos

Soils with a fragipan in one or more horizons or layers within 150 cm from the soil surface.

4.2.6 NEOSSOLOS QUARTZARÊNICOS Órticos gleissólicos

Soils with a gley horizon within 150 cm from the soil surface, that do not meet the requirements to be classified as Neossolos Quartzarênicos Hidromórficos.

4.2.7 NEOSSOLOS QUARTZARÊNICOS Órticos plintossólicos

Soils with a plinthic qualifier or plinthic horizon in a non-diagnostic position for Plintossolos within 150 cm from the soil surface.

4.2.8 NEOSSOLOS QUARTZARÊNICOS Órticos espodossólicos

Soils with a spodic qualifier within 150 cm from the soil surface.

4.2.9 NEOSSOLOS QUARTZARÊNICOS Órticos argissólicos

Soils that have lamellae with a sandy loam or finer texture with a total thickness of < 15 cm, not characterizing a textural B horizon, within 150 cm from the soil surface.

4.2.10 NEOSSOLOS QUARTZARÊNICOS Órticos latossólicos

Soils with a similar morphology to that of loamy textured Latossolos, with a loamy sand, nearly sandy loam texture and a weak structure development (very small granular), all within 150 cm from the soil surface.

4.2.11 NEOSSOLOS QUARTZARÊNICOS Órticos espesso-húmicos

Soils with a humic A horizon and carbon content of ≥ 10 g kg⁻¹to a depth of ≥ 80 cm.

4.2.12 NEOSSOLOS QUARTZARÊNICOS Órticos húmicos

Soils with a humic A horizon (Projeto RADAMBRASIL, 1975, p. 258, profile 45).

4.2.13 NEOSSOLOS QUARTZARÊNICOS Órticos típicos

Other soils that do not fit in the previous classes.

Notes

(38) Parameter in the test phase.

Chapter 13

Nitossolos

Nitossolos are soils composed of mineral material, with ≥ 350 g kg⁻¹ clay, including in the A horizon, and have a nitic B horizon below the A horizon. The nitic B horizon has low activity or high activity clay together with an aluminic qualifier, both in most of the first 100 cm of the B horizon (including BA).

The polychromy (color variation in the upper 150 cm of the soil), as described below, ought to be used as an additional criterion to distinguish Red or Yellow-Red Argissolos from Nitossolos in situations where the other characteristics coincide.

Nitossolos have practically no marked polychromy in the profile and must meet the following color criteria:

a) For soils with all colors of the A and B horizons, except BC, on the same hue page, variations of a maximum of 2 units for value and/or 3 units for chroma³⁹ are accepted;

b) For soils with colors of the A and B horizons, except BC, on two pages of hues, variations of ≤ 1 unit of value and ≤ 2 units of chroma³⁹ are accepted;

c) For soils with colors of the A and B horizons, except BC, on more than two pages of hues, variations in value are not acceptable, whereas a variation of ≤ 1 unit of chroma³⁹ is admissible.

Classes of the 2nd categorical level (suborders)

1 NITOSSOLOS BRUNOS⁴⁰

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Soils with a retractable qualifier and a humic A horizon or organic carbon content of > 10 g kg⁻¹ to a depth of 40 cm, which are brownish in the upper part of the B horizon (including BA), with predominant hues of 7.5YR or yellower, simultaneously with value ≤ 4 and chroma ≤ 6 when moist. Soils with a hue of 5YR in the upper part of the B horizon (including BA) are acceptable, provided the value is ≤ 4 and the chroma is < 6 when moist.

2 NITOSSOLOS VERMELHOS

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Soils with a hue of 2.5YR or redder in most of the first 100 cm of the B horizon (excluding BA).

3 NITOSSOLOS HÁPLICOS

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Other soils that do not fit in the previous classes.

Classes of the 3rd categorical level (great groups)

1 NITOSSOLOS BRUNOS

1.1 NITOSSOLOS BRUNOS Aluminoférricos

Soils with an aluminic qualifier and Fe₂O₃ (by H₂SO₄) contents from 150 g kg⁻¹ to < 360 g kg⁻¹ soil, both in most of the first 100 cm of the B horizon (including BA).

1.2 NITOSSOLOS BRUNOS Alumínicos

Soils with an aluminic qualifier in most of the first 100 cm of the B horizon (including BA).

1.3 NITOSSOLOS BRUNOS Distroférricos

Soils with a base saturation of < 50% and Fe₂O₃ (by H₂SO₄) contents from 150 g kg⁻¹ to < 360 g kg⁻¹ soil, both in most of the first 100 cm of the B horizon (including BA).

1.4 NITOSSOLOS BRUNOS Distróficos

Other soils with a base saturation of < 50% in most of the first 100 cm of the B horizon (including BA).

2 NITOSSOLOS VERMELHOS

2.1 NITOSSOLOS VERMELHOS Ta Alumínicos

Soils with high activity clay and an aluminic qualifier in most of the first 100 cm of the B horizon (including BA).

2.2 NITOSSOLOS VERMELHOS Alumínicos

Soils with an aluminic qualifier in most of the first 100 cm of the B horizon (including BA).

2.3 NITOSSOLOS VERMELHOS Distroférricos

Soils with a base saturation of < 50% and Fe₂O₃ (by H₂SO₄) contents of 150 g kg⁻¹ to < 360 g kg⁻¹ soil, both in most of the first 100 cm of the B horizon (including BA).

2.4 NITOSSOLOS VERMELHOS Distróficos

Soils with a base saturation of < 50% in most of the first 100 cm of the B horizon (including BA).

2.5 NITOSSOLOS VERMELHOS Eutroférricos

Soils with a base saturation of ≥ 50% and Fe₂O₃ (by H₂SO₄) contents from 150 g kg⁻¹ to < 360 g kg⁻¹ soil, both in most of the first 100 cm of the B horizon (including BA).

2.6 NITOSSOLOS VERMELHOS Eutróficos

Other soils with a base saturation of ≥ 50% in most of the first 100 cm of the B horizon (including BA).

3 NITOSSOLOS HÁPLICOS

3.1 NITOSSOLOS HÁPLICOS Ta Alumínicos

Soils with high activity clay and an aluminic qualifier in most of the first 100 cm of the B horizon (including BA).

3.2 NITOSSOLOS HÁPLICOS Alumínicos

Soils with an aluminic qualifier in most of the first 100 cm of the B horizon (including BA).

3.3 NITOSSOLOS HÁPLICOS Distróficos

Soils with a base saturation of < 50% in most of the first 100 cm of the B horizon (including BA).

3.4 NITOSSOLOS HÁPLICOS Eutróficos

Other soils with a base saturation of ≥ 50% in most of the first 100 cm of the B horizon (including BA).

Classes of the 4th categorical level (subgroups)

1.1 NITOSSOLOS BRUNOS Aluminoférricos

1.1.1 NITOSSOLOS BRUNOS Aluminoférricos rúbricos húmicos

Soils that have simultaneously a humic A horizon and a rubric qualifier within the first 100 cm of the B horizon (including BA).

1.1.2 NITOSSOLOS BRUNOS Aluminoférricos rúbricos

Soils with a rubric qualifier within the first 100 cm of the B horizon (including BA).

1.1.3 NITOSSOLOS BRUNOS Aluminoférricos húmicos

Soils with a humic A horizon.

1.1.4 NITOSSOLOS BRUNOS Aluminoférricos típicos

Other soils that do not fit in the previous classes.

1.2 NITOSSOLOS BRUNOS Alumínicos

1.2.1 NITOSSOLOS BRUNOS Alumínicos rúbricos húmicos

Soils that have simultaneously a humic A horizon and a rubric qualifier within the first 100 cm of the B horizon (including BA).

1.2.2 NITOSSOLOS BRUNOS Alumínicos rúbricos

Soils with a rubric qualifier within the first 100 cm of the B horizon (including BA).

1.2.3 NITOSSOLOS BRUNOS Alumínicos húmicos

Soils with a humic A horizon.

1.2.4 NITOSSOLOS BRUNOS Alumínicos típicos

Other soils that do not fit in the previous classes.

1.3 NITOSSOLOS BRUNOS Distroférricos

1.3.1 NITOSSOLOS BRUNOS Distroférricos rúbricos húmicos

Soils that have simultaneously a humic A horizon and a rubric qualifier within the first 100 cm of the B horizon (including BA).

1.3.2 NITOSSOLOS BRUNOS Distroférricos rúbricos

Soils with a rubric qualifier within the first 100 cm of the B horizon (including BA).

1.3.3 NITOSSOLOS BRUNOS Distroférricos húmicos

Soils with a humic A horizon.

1.3.4 NITOSSOLOS BRUNOS Distroférricos típicos

Other soils that do not fit in the previous classes.

1.4 NITOSSOLOS BRUNOS Distróficos

1.4.1 NITOSSOLOS BRUNOS Distróficos rúbricos húmicos

Soils that have simultaneously a humic A horizon and a rubric qualifier within the first 100 cm of the B horizon (including BA).

1.4.2 NITOSSOLOS BRUNOS Distróficos rúbricos

Soils with a rubric qualifier within the first 100 cm of the B horizon (including BA).

1.4.3 NITOSSOLOS BRUNOS Distróficos húmicos

Soils with a humic A horizon.

1.4.4 NITOSSOLOS BRUNOS Distróficos típicos

Other soils that do not fit in the previous classes.

2.1 NITOSSOLOS VERMELHOS Ta Alumínicos

2.1.1 NITOSSOLOS VERMELHOS Ta Alumínicos húmicos

Soils with a humic A horizon.

2.1.2 NITOSSOLOS VERMELHOS Ta Alumínicos típicos

Other soils that do not fit in the previous class.

2.2 NITOSSOLOS VERMELHOS Alumínicos

2.2.1 NITOSSOLOS VERMELHOS Alumínicos húmicos

Soils with a humic A horizon.

2.2.2 NITOSSOLOS VERMELHOS Alumínicos típicos

Other soils that do not fit in the previous class.

2.3 NITOSSOLOS VERMELHOS Distroférricos

2.3.1 NITOSSOLOS VERMELHOS Distroférricos latossólicos

Soils with a latosolic B horizon below the nitic B horizon within 150 cm from the soil surface.

2.3.2 NITOSSOLOS VERMELHOS Distroférricos típicos

Other soils that do not fit in the previous class.

2.4 NITOSSOLOS VERMELHOS Distróficos

2.4.1 NITOSSOLOS VERMELHOS Distróficos latossólicos

Soils with a latosolic B horizon below the nitic B horizon within 150 cm from the soil surface.

2.4.2 NITOSSOLOS VERMELHOS Distróficos típicos

Other soils that do not fit in the previous class.

2.5 NITOSSOLOS VERMELHOS Eutroférricos

2.5.1 NITOSSOLOS VERMELHOS Eutroférricos plintossólicos

Soils with a plinthic qualifier or plinthic horizon in a non-diagnostic position for Plintossolos within 150 cm from the soil surface.

2.5.2 NITOSSOLOS VERMELHOS Eutroférricos latossólicos

Soils with a latosolic B horizon below the nitic B horizon within 150 cm from the soil surface.

2.5.3 NITOSSOLOS VERMELHOS Eutroférricos chernossólicos

Soils with a chernozemic A horizon and clay activity ≥ 20 cmolc kg⁻¹ clay in most of the first 100 cm of the B horizon (including BA).

2.5.4 NITOSSOLOS VERMELHOS Eutroférricos típicos

Other soils that do not fit in the previous classes.

2.6 NITOSSOLOS VERMELHOS Eutróficos

2.6.1 NITOSSOLOS VERMELHOS Eutróficos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

2.6.2 NITOSSOLOS VERMELHOS Eutróficos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

2.6.3 NITOSSOLOS VERMELHOS Eutróficos latossólicos

Soils with a latosolic B horizon below the nitic B horizon within 150 cm from the soil surface.

2.6.4 NITOSSOLOS VERMELHOS Eutróficos chernossólicos

Soils with a chernozemic A horizon and clay activity ≥ 20 cmolc kg⁻¹ clay in most of the first 100 cm of the B horizon (including BA).

2.6.5 NITOSSOLOS VERMELHOS Eutróficos típicos

Other soils that do not fit in the previous classes.

3.1 NITOSSOLOS HÁPLICOS Ta Alumínicos

3.1.1 NITOSSOLOS HÁPLICOS Ta Alumínicos típicos

All the Nitossolos Háplicos Ta Alumínicos (provisionally).

3.2 NITOSSOLOS HÁPLICOS Alumínicos

3.2.1 NITOSSOLOS HÁPLICOS Alumínicos latossólicos

Soils with a latosolic B horizon below the nitic B horizon within 150 cm from the soil surface.

3.2.2 NITOSSOLOS HÁPLICOS Alumínicos típicos

Other soils that do not fit in the previous class.

3.3 NITOSSOLOS HÁPLICOS Distróficos

3.3.1 NITOSSOLOS HÁPLICOS Distróficos latossólicos

Soils with a latosolic B horizon below the nitic B horizon within 150 cm from the soil surface.

3.3.2 NITOSSOLOS HÁPLICOS Distróficos húmicos

Soils with a humic A horizon.

3.3.3 NITOSSOLOS HÁPLICOS Distróficos típicos

Other soils that do not fit in the previous classes.

3.4 NITOSSOLOS HÁPLICOS Eutróficos

3.4.1 NITOSSOLOS HÁPLICOS Eutróficos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.4.2 NITOSSOLOS HÁPLICOS Eutróficos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.4.3 NITOSSOLOS HÁPLICOS Eutróficos chernossólicos

Soils with a chernozemic A horizon and clay activity ≥ 20 cmolc kg⁻¹ clay in most of the first 100 cm of the B horizon (including BA).

3.4.4 NITOSSOLOS HÁPLICOS Eutróficos típicos

Other soils that do not fit in the previous classes.

Notes

(39) Acceptable are chroma variations of one unit more than that indicated for intermediate soils (latosolic, rubric etc.) or when the difference occurs between the uppermost A horizon and the horizon(s) of the lower part of the profile, at a depth of > 100 cm from the soil surface.

(40) Soils identified to date on the plateaus of Rio Grande do Sul, Santa Catarina and Paraná and in the region of Poços de Caldas, MG. Criteria in the validation phase.

Chapter 14

Organossolos

Organossolos are soils consisting of organic material that have a histic horizon, which must meet the following criteria:

At least 60 cm thick if ≥ 75% (expressed in volume) of the organic material consists of plant tissue in the form of residues of fine branches, fine roots, tree bark etc., excluding live plant parts; or

Be saturated with water for ≤ 30 consecutive days per year, during the rainy season and have a histic O horizon with the following thicknesses:

Thickness of ≥ 20 cm when overlying a fragmentary lithic or lithic contact or a horizon and/or layer consisting of ≥ 90% (in volume) of mineral material with a diameter of > 2 mm (gravel, pebbles and boulders); or

Thickness of ≥ 40 cm when overlying A, B and/or C horizons; or

Be saturated with water during most of the year, in most years, unless artificially drained, having a histic H horizon with a thickness of ≥ 40 cm, either extending in a single section from the soil surface downwards, or taken cumulatively, within the 80 cm below the surface.

Classes of the 2nd categorical level (suborders)

1 ORGANOSSOLOS TIOMÓRFICOS

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Soils with sulfidic materials in one or more horizons or layers or a sulfuric horizon, both within 100 cm from the soil surface.

2 ORGANOSSOLOS FÓLICOS

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Soils that are saturated with water for ≤ 30 consecutive days per year, during the rainy season, and have a histic O horizon.

3 ORGANOSSOLOS HÁPLICOS

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Other soils that do not fit in the previous classes.

Classes of the 3rd categorical level (great groups)

1 ORGANOSSOLOS TIOMÓRFICOS

1.1 ORGANOSSOLOS TIOMÓRFICOS Fíbricos

Soils with fibric organic material in most part of the horizons and/or layers within 100 cm from the soil surface.

1.2 ORGANOSSOLOS TIOMÓRFICOS Hêmicos

Soils with hemic organic material in most part of the horizons and/or layers within 100 cm from the soil surface.

1.3 ORGANOSSOLOS TIOMÓRFICOS Sápricos

Soils with sapric organic material in most part of the horizons and/or layers within 100 cm from the soil surface.

2 ORGANOSSOLOS FÓLICOS

2.1 ORGANOSSOLOS FÓLICOS Fíbricos

Soils with fibric organic material in most part of the horizons and/or layers within 100 cm from the soil surface.

2.2 ORGANOSSOLOS FÓLICOS Hêmicos

Soils with hemic organic material in most part of the horizons and/or layers within 100 cm from the soil surface.

2.3 ORGANOSSOLOS FÓLICOS Sápricos

Soils with sapric organic material in most part of the horizons and/or layers within 100 cm from the soil surface.

3 ORGANOSSOLOS HÁPLICOS

3.1 ORGANOSSOLOS HÁPLICOS Fíbricos

Soils with fibric organic material in most part of the horizons and/or layers within 100 cm from the soil surface (Kämpf; Schneider, 1989, p. 230, Unit Torres 4).

3.2 ORGANOSSOLOS HÁPLICOS Hêmicos

Soils with hemic organic material in most part of the horizons and/or layers within 100 cm from the soil surface (Kämpf; Schneider, 1989, p. 230, Unit Barcelos 1).

3.3 ORGANOSSOLOS HÁPLICOS Sápricos

Soils with sapric organic material in most part of the horizons and/or layers within 100 cm from the soil surface (Kämpf; Schneider, 1989, p. 230, Unit Caldas 1).

Classes of the 4th categorical level (subgroups)

1.1 ORGANOSSOLOS TIOMÓRFICOS Fíbricos

1.1.1 ORGANOSSOLOS TIOMÓRFICOS Fíbricos salinos

Soils with a saline qualifier in one or more horizons or layers within 150 cm from the soil surface.

1.1.2 ORGANOSSOLOS TIOMÓRFICOS Fíbricos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

1.1.3 ORGANOSSOLOS TIOMÓRFICOS Fíbricos térricos

Soils with horizons and/or layers consisting of mineral materials (A, Ag, Big and/or Cg horizon), with a (continuous or cumulative) thickness of > 30 cm, within 100 cm from the soil surface.

1.1.4 ORGANOSSOLOS TIOMÓRFICOS Fíbricos típicos

Other soils that do not fit in the previous classes (this class is typically represented by soils with a salic qualifier within 100 cm from the soil surface).

1.2 ORGANOSSOLOS TIOMÓRFICOS Hêmicos

1.2.1 ORGANOSSOLOS TIOMÓRFICOS Hêmicos salinos

Soils with a saline qualifier in one or more horizons or layers within 150 cm from the soil surface.

1.2.2 ORGANOSSOLOS TIOMÓRFICOS Hêmicos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

1.2.3 ORGANOSSOLOS TIOMÓRFICOS Hêmicos térricos

Soils with horizons and/or layers consisting of mineral materials (A, Ag, Big and/or Cg horizon), with a (continuous or cumulative) thickness of > 30 cm, within 100 cm from the soil surface.

1.2.4 ORGANOSSOLOS TIOMÓRFICOS Hêmicos típicos

Other soils that do not fit in the previous classes (this class is typically represented by soils with a salic qualifier within 100 cm from the soil surface).

1.3 ORGANOSSOLOS TIOMÓRFICOS Sápricos

1.3.1 ORGANOSSOLOS TIOMÓRFICOS Sápricos salinos

Soils with a saline qualifier in one or more horizons or layers within 150 cm from the soil surface.

1.3.2 ORGANOSSOLOS TIOMÓRFICOS Sápricos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

1.3.3 ORGANOSSOLOS TIOMÓRFICOS Sápricos térricos

Soils with horizons and/or layers consisting of mineral materials (A, Ag, Big and/or Cg horizon), with a (continuous or cumulative) thickness of > 30 cm, within 100 cm from the soil surface.

1.3.4 ORGANOSSOLOS TIOMÓRFICOS Sápricos típicos

Other soils that do not fit in the previous classes (this class is typically represented by soils with a salic qualifier within 100 cm from the soil surface).

2.1 ORGANOSSOLOS FÓLICOS Fíbricos

2.1.1 ORGANOSSOLOS FÓLICOS Fíbricos fragmentários

Soils with a fragmentary lithic contact within 50 cm from the soil surface.

2.1.2 ORGANOSSOLOS FÓLICOS Fíbricos líticos

Soils with a lithic contact within 50 cm from the soil surface.

2.1.3 ORGANOSSOLOS FÓLICOS Fíbricos cambissólicos

Soils with an incipient B horizon below the histic or A horizon.

2.1.4 ORGANOSSOLOS FÓLICOS Fíbricos típicos

Other soils that do not fit in the previous classes.

2.2 ORGANOSSOLOS FÓLICOS Hêmicos

2.2.1 ORGANOSSOLOS FÓLICOS Hêmicos fragmentários

Soils with a fragmentary lithic contact within 50 cm from the soil surface.

2.2.2 ORGANOSSOLOS FÓLICOS Hêmicos líticos

Soils with a lithic contact within 50 cm from the soil surface.

2.2.3 ORGANOSSOLOS FÓLICOS Hêmicos cambissólicos

Soils with an incipient B horizon below the histic or A horizon.

2.2.4 ORGANOSSOLOS FÓLICOS Hêmicos típicos

Other soils that do not fit in the previous classes.

2.3 ORGANOSSOLOS FÓLICOS Sápricos

2.3.1 ORGANOSSOLOS FÓLICOS Sápricos fragmentários

Soils with a fragmentary lithic contact within 50 cm from the soil surface.

2.3.2 ORGANOSSOLOS FÓLICOS Sápricos líticos

Soils with a lithic contact within 50 cm from the soil surface.

2.3.3 ORGANOSSOLOS FÓLICOS Sápricos cambissólicos

Soils with an incipient B horizon below the histic or A horizon (Antonello, 1983, p. 32 and 195, profile P3).

2.3.4 ORGANOSSOLOS FÓLICOS Sápricos típicos

Other soils that do not fit in the previous classes.

3.1 ORGANOSSOLOS HÁPLICOS Fíbricos

3.1.1 ORGANOSSOLOS HÁPLICOS Fíbricos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.1.2 ORGANOSSOLOS HÁPLICOS Fíbricos térricos

Soils with horizons and/or layers consisting of mineral materials (A, Ag, Big and/or Cg horizon), with a (continuous or cumulative) thickness of > 30 cm, within 100 cm from the soil surface.

3.1.3 ORGANOSSOLOS HÁPLICOS Fíbricos típicos

Other soils that do not fit in the previous classes.

3.2 ORGANOSSOLOS HÁPLICOS Hêmicos

3.2.1 ORGANOSSOLOS HÁPLICOS Hêmicos carbonáticos

Soils with a carbonatic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.2.2 ORGANOSSOLOS HÁPLICOS Hêmicos sódicos

Soils with a sodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.2.3 ORGANOSSOLOS HÁPLICOS Hêmicos sálicos

Soils with a salic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.2.4 ORGANOSSOLOS HÁPLICOS Hêmicos salinos

Soils with a saline qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.2.5 ORGANOSSOLOS HÁPLICOS Hêmicos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.2.6 ORGANOSSOLOS HÁPLICOS Hêmicos térricos

Soils with horizons and/or layers consisting of mineral materials (A, Ag, Big and/or Cg horizon), with a (continuous or cumulative) thickness of > 30 cm, within 100 cm from the soil surface.

3.2.7 ORGANOSSOLOS HÁPLICOS Hêmicos típicos

Other soils that do not fit in the previous classes.

3.3 ORGANOSSOLOS HÁPLICOS Sápricos

3.3.1 ORGANOSSOLOS HÁPLICOS Sápricos carbonáticos

Soils with a carbonatic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.3.2 ORGANOSSOLOS HÁPLICOS Sápricos sódicos

Soils with a sodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.3.3 ORGANOSSOLOS HÁPLICOS Sápricos sálicos

Soils with a salic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.3.4 ORGANOSSOLOS HÁPLICOS Sápricos salinos

Soils with a saline qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.3.5 ORGANOSSOLOS HÁPLICOS Sápricos hipocarbonáticos solódicos térricos

Soils with hypocarbonatic and solodic qualifiers in one or more horizons or layers within 150 cm from the soil surface and which, additionally, have horizons and/or layers consisting of mineral materials (A, Ag, Big and/or Cg horizons) with a thickness (continuous or cumulative) of > 30 cm within 100 cm from the soil surface (Palmieri; Santos, 1980, p. 283, profile GB-48).

3.3.6 ORGANOSSOLOS HÁPLICOS Sápricos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.3.7 ORGANOSSOLOS HÁPLICOS Sápricos térricos

Soils with horizons and/or layers consisting of mineral materials (A, Ag, Big and/or Cg horizon), with a thickness (continuous or cumulative) of > 30 cm, within 100 cm from the soil surface (Larach et al., 1984, v. 2, p. 707, complementary profile 137).

3.3.8 ORGANOSSOLOS HÁPLICOS Sápricos típicos

Other soils that do not fit in the previous classes (Conceição, 1989, p. 163, profile PRV 2).

Chapter 15

Planossolos

Planossolos are soils composed of mineral material with an A or E horizon followed by a planic B horizon. A planic horizon with no sodic qualifier has no taxonomic precedence over the plinthic horizon.

Classes of the 2nd categorical level (suborders)

1 PLANOSSOLOS NÁTRICOS

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Soils with a planic horizon and: a) a sodic qualifier immediately below an A or E horizon within 200 cm from the soil surface; or b) a sodic qualifier in one or more horizons within 150 cm from the soil surface, provided that the sum of exchangeable Mg²⁺ + Na⁺ is > Ca²⁺ + H⁺ in the upper part of the B horizon (Reunião..., 1979a, profile PRJ 17; Romero et al., 2009, profile 4).

2 PLANOSSOLOS HÁPLICOS

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Other soils that do not fit in the previous class.

Classes of the 3rd categorical level (great groups)

1 PLANOSSOLOS NÁTRICOS

1.1 PLANOSSOLOS NÁTRICOS Carbonáticos

Soils with a carbonatic qualifier in one or more horizons or layers or with a calcic horizon, both in the upper 150 cm of the soil. If the planic B horizon occurs at a depth of > 150 cm and ≤ 200 cm, the carbonatic qualifier or calcic horizon must be immediately below the A or E horizon (Jacomine et al., 1977-1979, v. 2, p. 871, profile 273).

1.2 PLANOSSOLOS NÁTRICOS Sálicos

Soils with a salic qualifier in one or more horizons or layers in the upper 150 cm of the soil. If the planic B horizon occurs at a depth of > 150 cm and ≤ 200 cm, the salic qualifier must be immediately below the A or E horizon (Jacomine et al., 1975b, p. 279, profile 58).

1.3 PLANOSSOLOS NÁTRICOS Órticos

Other soils that do not fit in the previous classes.

2 PLANOSSOLOS HÁPLICOS

2.1 PLANOSSOLOS HÁPLICOS Carbonáticos

Soils with a carbonatic qualifier in one or more horizons or layers or with a calcic horizon, both in the upper 150 cm of the soil. If the planic B horizon occurs at a depth of > 150 cm and ≤ 200 cm, the carbonatic qualifier or calcic horizon must be immediately below the A or E horizon.

2.2 PLANOSSOLOS HÁPLICOS Sálicos

Soils with a salic qualifier in one or more horizons or layers in the upper 150 cm of the soil. If the planic B horizon occurs at a depth of > 150 cm and ≤ 200 cm, the salic qualifier must be immediately below the A or E horizon.

2.3 PLANOSSOLOS HÁPLICOS Alumínicos

Soils with an aluminic qualifier in most of the B horizon (including BA), in the upper 150 cm of the soil. If the planic B horizon occurs at a depth of ≥ 150 cm, most of it must be within the upper 200 cm of the soil surface.

2.4 PLANOSSOLOS HÁPLICOS Distróficos

Soils with a base saturation of < 50% in most of the B horizon (including BA or BE) in the upper 150 cm of the soil. If the planic B horizon occurs at a depth of > 150 cm, most of it must be within the upper 200 cm of the soil.

2.5 PLANOSSOLOS HÁPLICOS Eutróficos

Soils with a base saturation of ≥ 50% in most of the B horizon (including BA or BE) within 150 cm from the soil surface (Lemos, 1973, p. 250, profile RS-109). If the planic B horizon occurs at a depth of ≥ 150 cm, most part of it must be within the upper 200 cm of the soil (Lemos, 1973, p. 250, profile RS-109).

Classes of the 4th categorical level (subgroups)

1.1 PLANOSSOLOS NÁTRICOS Carbonáticos

1.1.1 PLANOSSOLOS NÁTRICOS Carbonáticos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or a vertic qualifier in one or more horizons or layers, within 150 cm from the soil surface.

1.1.2 PLANOSSOLOS NÁTRICOS Carbonáticos típicos

Other soils that do not fit in the previous class.

1.2 PLANOSSOLOS NÁTRICOS Sálicos

1.2.1 PLANOSSOLOS NÁTRICOS Sálicos espessarênicos

Soils with a sandy texture from the surface to a depth of > 100 cm and ≤ 200 cm.

1.2.2 PLANOSSOLOS NÁTRICOS Sálicos arênicos

Soils with a sandy texture from the surface to a depth of ≥ 50 cm and ≤100 cm.

1.2.3 PLANOSSOLOS NÁTRICOS Sálicos espessos

Soils with a sandy loam or finer texture in one or more horizons from the soil surface to the upper part of the planic B horizon, which occurs at a depth of > 100 cm and ≤ 200 cm.

1.2.4 PLANOSSOLOS NÁTRICOS Sálicos mésicos

Soils with a sandy loam or finer texture in one or more horizons from the soil surface to the upper part of the planic B horizon, which occurs at a depth of > 50 cm and ≤ 100 cm.

1.2.5 PLANOSSOLOS NÁTRICOS Sálicos dúricos

Soils with a duric qualifier in one or more horizons or layers within 150 cm from the soil surface (Reunião..., 1979a, profile 17).

1.2.6 PLANOSSOLOS NÁTRICOS Sálicos neofluvissólicos

Soils with a fluvic qualifier within 150 cm from the soil surface (Reunião..., 1998, p. 62, profile 10).

1.2.7 PLANOSSOLOS NÁTRICOS Sálicos típicos

Other soils that do not fit in the previous classes.

1.3 PLANOSSOLOS NÁTRICOS Órticos

1.3.1 PLANOSSOLOS NÁTRICOS Órticos salinos

Soils with a saline qualifier in one or more horizons or layers within 150 cm from the soil surface (Jacomine et al., 1973, profile 99).

1.3.2 PLANOSSOLOS NÁTRICOS Órticos espessarênicos

Soils with a sandy texture from the surface to a depth of > 100 cm and ≤ 200 cm.

1.3.3 PLANOSSOLOS NÁTRICOS Órticos arênicos

Soils with a sandy texture from the surface to a depth of ≥ 50 cm and ≤100 cm (Rodrigues; Santos, 1980, profile 35).

1.3.4 PLANOSSOLOS NÁTRICOS Órticos espessos

Soils with a sandy loam or finer texture in one or more horizons from the soil surface to the upper part of the planic B horizon, which occurs at a depth of > 100 cm and ≤ 200 cm.

1.3.5 PLANOSSOLOS NÁTRICOS Órticos mésicos

Soils with a sandy loam or finer texture in one or more horizons from the soil surface to the upper part of the planic B horizon, which occurs at a depth of ≥ 50 cm and ≤100 cm.

1.3.6 PLANOSSOLOS NÁTRICOS Órticos dúricos

Soils with a duric qualifier in one or more horizons or layers within 150 cm from the soil surface.

1.3.7 PLANOSSOLOS NÁTRICOS Órticos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or a vertic qualifier in one or more horizons or layers within 150 cm from the soil surface.

1.3.8 PLANOSSOLOS NÁTRICOS Órticos gleissólicos

Soils with a gley horizon within the first 50 cm or between 50 cm and 100 cm, provided they are preceded by predominantly grayish horizons.

1.3.9 PLANOSSOLOS NÁTRICOS Órticos plintossólicos

Soils with a plinthic qualifier or plinthic horizon in a non-diagnostic position for Plintossolos within 150 cm from the soil surface.

1.3.10 PLANOSSOLOS NÁTRICOS Órticos típicos

Other soils that do not fit in the previous classes (Jacomine et al., 1972-1973, profile 96).

2.1 PLANOSSOLOS HÁPLICOS Carbonáticos

2.1.1 PLANOSSOLOS HÁPLICOS Carbonáticos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface (Jacomine et al., 1977-1979, profile 219).

2.1.2 PLANOSSOLOS HÁPLICOS Carbonáticos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or a vertic qualifier in one or more horizons or layers within 150 cm from the soil surface.

2.1.3 PLANOSSOLOS HÁPLICOS Carbonáticos típicos

Other soils that do not fit in the previous classes (Jacomine et al., 1977-1979, profile 197).

2.2 PLANOSSOLOS HÁPLICOS Sálicos

2.2.1 PLANOSSOLOS HÁPLICOS Sálicos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

2.2.2 PLANOSSOLOS HÁPLICOS Sálicos arênicos

Soils with a sandy texture from the surface to a depth of ≥ 50 cm and ≤100 cm.

2.2.3 PLANOSSOLOS HÁPLICOS Sálicos espessos

Soils with a sandy loam or finer texture in one or more horizons from the soil surface to the upper part of the planic B horizon, which occurs at a depth of > 100 cm and ≤ 200 cm.

2.2.4 PLANOSSOLOS HÁPLICOS Sálicos mésicos

Soils with a sandy loam or finer texture in one or more horizons from the soil surface to the upper part of the planic B horizon, which occurs at a depth of ≥ 50 cm and ≤100 cm.

2.2.5 PLANOSSOLOS HÁPLICOS Sálicos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or a vertic qualifier in one or more horizons or layers within 150 cm from the soil surface.

2.2.6 PLANOSSOLOS HÁPLICOS Sálicos gleissólicos

Soils with a gley horizon within the first 50 cm or between 50 cm and 100 cm, provided they are preceded by predominantly grayish horizons.

2.2.7 PLANOSSOLOS HÁPLICOS Sálicos típicos

Other soils that do not fit in the previous classes.

2.3 PLANOSSOLOS HÁPLICOS Alumínicos

2.3.1 PLANOSSOLOS HÁPLICOS Alumínicos arênicos

Soils with a sandy texture from the surface to a depth of ≥ 50 cm and ≤100 cm.

2.3.2 PLANOSSOLOS HÁPLICOS Alumínicos espessos

Soils with a sandy loam or finer texture in one or more horizons from the soil surface to the upper part of the planic B horizon, which occurs at a depth of > 100 cm and ≤ 200 cm.

2.3.3 PLANOSSOLOS HÁPLICOS Alumínicos mésicos

Soils with a sandy loam or finer texture in one or more horizons from the soil surface to the upper part of the planic B horizon, which occurs at a depth of ≥ 50 cm and ≤ 100 cm.

2.3.4 PLANOSSOLOS HÁPLICOS Alumínicos gleissólicos

Soils with a gley horizon within the first 50 cm or between 50 cm and 100 cm, provided they are preceded by predominantly grayish horizons.

2.3.5 PLANOSSOLOS HÁPLICOS Alumínicos típicos

Other soils that do not fit in the previous classes.

2.4 PLANOSSOLOS HÁPLICOS Distróficos

2.4.1 PLANOSSOLOS HÁPLICOS Distróficos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

2.4.2 PLANOSSOLOS HÁPLICOS Distróficos espessarênicos

Soils with a sandy texture from the surface to a depth of > 100 cm and ≤ 200 cm (Rodrigues; Santos, 1980, profile 36).

2.4.3 PLANOSSOLOS HÁPLICOS Distróficos arênicos gleissólicos

Soils with a sandy texture from the surface to a depth of ≥ 50 cm and ≤100 cm and with a gley horizon within the first 50 cm or between 50 cm and 100 cm, provided they are preceded by predominantly grayish horizons (Reunião..., 1983, profile IIRCC-1 RJ).

2.4.4 PLANOSSOLOS HÁPLICOS Distróficos arênicos

Soils with a sandy texture from the surface to a depth of ≤ 50 cm and ≥ 100 cm (Palmieri; Santos, 1980, profile 30).

2.4.5 PLANOSSOLOS HÁPLICOS Distróficos espessos

Soils with a sandy loam or finer texture in one or more horizons from the soil surface to the upper part of the planic B horizon, which occurs at a depth of > 100 cm and ≤ 200 cm.

2.4.6 PLANOSSOLOS HÁPLICOS Distróficos mésicos

Soils with a sandy loam or finer texture in one or more horizons from the soil surface to the upper part of the planic B horizon, which occurs at a depth of ≥ 50 cm and ≤100 cm.

2.4.7 PLANOSSOLOS HÁPLICOS Distróficos gleissólicos

Soils with a gley horizon within the first 50 cm or between 50 cm and 100 cm, provided they are preceded by predominantly grayish horizons.

2.4.8 PLANOSSOLOS HÁPLICOS Distróficos plintossólicos

Soils with a plinthic qualifier or plinthic horizon in a non-diagnostic position for Plintossolos within 150 cm from the soil surface.

2.4.9 PLANOSSOLOS HÁPLICOS Distróficos típicos

Other soils that do not fit in the previous classes.

2.5 PLANOSSOLOS HÁPLICOS Eutróficos

2.5.1 PLANOSSOLOS HÁPLICOS Eutróficos salinos

Soils with a saline qualifier in one or more horizons or layers within 150 cm from the soil surface.

2.5.2 PLANOSSOLOS HÁPLICOS Eutróficos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface (Jacomine et al., 1977-1979, profile 200).

2.5.3 PLANOSSOLOS HÁPLICOS Eutróficos espessarênicos

Soils with a sandy texture from the surface to a depth of > 100 cm and ≤ 200 cm.

2.5.4 PLANOSSOLOS HÁPLICOS Eutróficos arênicos

Soils with a sandy texture from the surface to a depth of ≥ 50 cm and ≤100 cm (Jacomine et al., 1977-1979, profile 193).

2.5.5 PLANOSSOLOS HÁPLICOS Eutróficos espessos

Soils with a sandy loam or finer texture in one or more horizons from the soil surface to the upper part of the planic B horizon, which occurs at a depth of >100 cm and ≤ 200 cm.

2.5.6 PLANOSSOLOS HÁPLICOS Eutróficos mésicos

Soils with a sandy loam or finer texture in one or more horizons from the soil surface to the upper part of the planic B horizon, which occurs at a depth of ≥ 50 cm and ≤100 cm.

2.5.7 PLANOSSOLOS HÁPLICOS Eutróficos vertissólicos

Soils with a vertic horizon in a non-diagnostic position for Vertissolos or a vertic qualifier in one or more horizons or layers within 150 cm from the soil surface.

2.5.8 PLANOSSOLOS HÁPLICOS Eutróficos gleissólicos

Soils with a gley horizon within the first 50 cm or between 50 cm and 100 cm, provided they are preceded by predominantly grayish horizons.

2.5.9 PLANOSSOLOS HÁPLICOS Eutróficos chernossólicos

Soils with a chernozemic A horizon and clay activity ≥ 20 cmolc kg⁻¹ clay in most of the first 100 cm of the B horizon (including BA).

2.5.10 PLANOSSOLOS HÁPLICOS Eutróficos típicos

Other soils that do not fit in the previous classes.

Chapter 16

Plintossolos

Plintossolos are soils composed of mineral material, which have a plinthic, lithoplinthic or concretionary horizon and fulfill one of the following conditions:

Start within 40 cm from the surface; or

Start within 200 cm from the surface, when preceded by a gley horizon or immediately below the A, E horizon or another pale, variegated horizon or with abundant mottles.

When preceded by a pale (grayish or light yellowish) horizon or layer, Plintossolos must have colors between the hues and chromas defined in items (a) and (b) below, and may or may not have reddish to yellowish mottles.

When preceded by variegated horizons or layers, at least one of the colors must meet the conditions of items (a) and (b) defined below.

When preceded by horizons or layers with a reddish or yellowish matrix, the mottles must occur in abundant quantities (> 20% by volume) and have hues and chromas as defined in items (a) and (b):

Hue 5Y; or

Hues 7.5YR, 10YR or 2.5Y with chroma ≤ 4.

Classes of the 2nd categorical level (suborders)

1 PLINTOSSOLOS PÉTRICOS

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Soils with a concretionary horizon or lithoplinthic horizon, except when preceded by a plinthic horizon.

2 PLINTOSSOLOS ARGILÚVICOS

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Soils with a plinthic horizon and textural B horizon or an argiluvic qualifier.

3 PLINTOSSOLOS HÁPLICOS

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Other soils that do not fit in the previous classes.

Classes of the 3rd categorical level (great groups)

1 PLINTOSSOLOS PÉTRICOS

1.1 PLINTOSSOLOS PÉTRICOS Litoplínticos

Soils with a lithoplinthic horizon in diagnostic position within 200 cm from the soil surface.

1.2 PLINTOSSOLOS PÉTRICOS Concrecionários

Soils with a concretionary horizon in diagnostic position within 200 cm from the soil surface.

2 PLINTOSSOLOS ARGILÚVICOS

2.1 PLINTOSSOLOS ARGILÚVICOS Alumínicos

Soils with an aluminic qualifier in most of the first 100 cm of the B and/or C horizons (including BA or CA) (Jacomine, 1986a, v. 1, p. 424, profile 90).

2.2 PLINTOSSOLOS ARGILÚVICOS Distróficos

Soils with a base saturation of < 50% in most of the first 100 cm of the B and/or C horizons (including BA or CA).

2.3 PLINTOSSOLOS ARGILÚVICOS Eutróficos

Soils with a base saturation of ≥ 50% in most of the first 100 cm of the B and/or C horizons (including BA or CA).

3 PLINTOSSOLOS HÁPLICOS

3.1 PLINTOSSOLOS HÁPLICOS Ácricos

Soils with an acric qualifier in one or more horizons within 150 cm from the soil surface.

3.2 PLINTOSSOLOS HÁPLICOS Alumínicos

Soils with an aluminic qualifier in most of the first 100 cm of the B and/or C horizons (including BA or CA).

3.3 PLINTOSSOLOS HÁPLICOS Distróficos

Soils with a base saturation of < 50% in most of the first 100 cm of the B and/or C horizons (including BA or CA) (Reunião..., 1995, p. 28, profile 5-ES).

3.4 PLINTOSSOLOS HÁPLICOS Eutróficos

Soils with a base saturation of ≥ 50% in most of the first 100 cm of the B and/or C horizons (including BA or CA).

Classes of the 4th categorical level (subgroups)

1.1 PLINTOSSOLOS PÉTRICOS Litoplínticos

1.1.1 PLINTOSSOLOS PÉTRICOS Litoplínticos arênicos

Soils with a sandy texture from the surface to a depth of ≥ 50 cm and ≤100 cm.

1.1.2 PLINTOSSOLOS PÉTRICOS Litoplínticos êndicos

Soils with a lithoplinthic horizon at a depth of ≥ 40 cm from the soil surface.

1.1.3 PLINTOSSOLOS PÉTRICOS Litoplínticos gleissólicos

Soils with a gley horizon within 150 cm from the soil surface or down to the lithoplinthic horizon.

1.1.4 PLINTOSSOLOS PÉTRICOS Litoplínticos húmicos

Solis with a humic A horizon.

1.1.5 PLINTOSSOLOS PÉTRICOS Litoplínticos típicos

Other soils that do not fit in the previous classes.

1.2 PLINTOSSOLOS PÉTRICOS Concrecionários

1.2.1 PLINTOSSOLOS PÉTRICOS Concrecionários fragmentários

Soils with a fragmentary lithic contact within 50 cm from the soil surface.

1.2.2 PLINTOSSOLOS PÉTRICOS Concrecionários líticos

Soils with a lithic contact within 50 cm from the soil surface.

1.2.3 PLINTOSSOLOS PÉTRICOS Concrecionários leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

1.2.4 PLINTOSSOLOS PÉTRICOS Concrecionários lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

1.2.5 PLINTOSSOLOS PÉTRICOS Concrecionários êutricos

Soils with a eutric qualifier in the major part of the horizons and/or layers within 100 cm from the soil surface.

1.2.6 PLINTOSSOLOS PÉTRICOS Concrecionários êndicos

Soils with a concretionary horizon at depths of ≥ 40 cm from the soil surface.

1.2.7 PLINTOSSOLOS PÉTRICOS Concrecionários gleissólicos

Soils with a gley horizon within 150 cm from the soil surface.

1.2.8 PLINTOSSOLOS PÉTRICOS Concrecionários argissólicos

Soils with a textural B horizon or an argiluvic qualifier within 150 cm from the surface, coinciding or not with the concretionary horizon.

1.2.9 PLINTOSSOLOS PÉTRICOS Concrecionários latossólicos

Soils with a latosolic B horizon within 150 cm from the soil surface, coinciding or not with the concretionary horizon.

1.2.10 PLINTOSSOLOS PÉTRICOS Concrecionários cambissólicos

Soils with an incipient B horizon within 150 cm from the surface, coinciding or not with the concretionary horizon.

1.2.11 PLINTOSSOLOS PÉTRICOS Concrecionários húmicos

Soils with a humic A horizon.

1.2.12 PLINTOSSOLOS PÉTRICOS Concrecionários típicos

Other soils that do not fit in the previous classes.

2.1 PLINTOSSOLOS ARGILÚVICOS Alumínicos

2.1.1 PLINTOSSOLOS ARGILÚVICOS Alumínicos espessarênicos

Soils with a sandy texture from the surface to a depth of > 100 cm and ≤ 200 cm.

2.1.2 PLINTOSSOLOS ARGILÚVICOS Alumínicos arênicos

Soils with a sandy texture from the surface to a depth of ≥ 50 cm and ≤100 cm.

2.1.3 PLINTOSSOLOS ARGILÚVICOS Alumínicos espessos

Soils with a sandy loam or finer texture in one or more horizons from the soil surface to the top of the plinthic horizon, which occurs at a depth of > 100 cm and ≤ 200 cm.

2.1.4 PLINTOSSOLOS ARGILÚVICOS Alumínicos abrúpticos

Soils with an abrupt textural change (Jacomine, 1986a, v. 1, p. 431, profile 92).

2.1.5 PLINTOSSOLOS ARGILÚVICOS Alumínicos gleissólicos

Soils with a gley horizon within the first 50 cm or between 50 cm and 100 cm, provided they are preceded by predominantly grayish horizons (Reunião..., 2017, profile RO-11).

2.1.6 PLINTOSSOLOS ARGILÚVICOS Alumínicos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons within 150 cm from the soil surface.

2.1.7 PLINTOSSOLOS ARGILÚVICOS Alumínicos húmicos

Solis with humic A horizon.

2.1.8 PLINTOSSOLOS ARGILÚVICOS Alumínicos típicos

Other soils that do not fit in the previous classes.

2.2 PLINTOSSOLOS ARGILÚVICOS Distróficos

2.2.1 PLINTOSSOLOS ARGILÚVICOS Distróficos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

2.2.2 PLINTOSSOLOS ARGILÚVICOS Distróficos espessarênicos

Soils with a sandy texture from the surface to a depth of > 100 cm and ≤ 200 cm.

2.2.3 PLINTOSSOLOS ARGILÚVICOS Distróficos arênicos

Soils with a sandy texture from the surface to a depth of ≥ 50 cm and ≤100 cm.

2.2.4 PLINTOSSOLOS ARGILÚVICOS Distróficos espessos

Soils with a sandy loam or finer texture in one or more horizons from the soil surface to the top of the plinthic horizon, which occurs at a depth of > 100 cm and ≤ 200 cm.

2.2.5 PLINTOSSOLOS ARGILÚVICOS Distróficos abrúpticos

Solis with an abrupt textural change.

2.2.6 PLINTOSSOLOS ARGILÚVICOS Distróficos gleissólicos

Soils with a gley horizon within the first 50 cm or between 50 cm and 100 cm, provided they are preceded by predominantly grayish horizons.

2.2.7 PLINTOSSOLOS ARGILÚVICOS Distróficos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons within 150 cm from the soil surface.

2.2.8 PLINTOSSOLOS ARGILÚVICOS Distróficos húmicos

Solis with a humic A horizon.

2.2.9 PLINTOSSOLOS ARGILÚVICOS Distróficos típicos

Other soils that do not fit in the previous classes.

2.3 PLINTOSSOLOS ARGILÚVICOS Eutróficos

2.3.1 PLINTOSSOLOS ARGILÚVICOS Eutróficos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

2.3.2 PLINTOSSOLOS ARGILÚVICOS Eutróficos espessarênicos

Soils with a sandy texture from the surface to a depth of > 100 cm and ≤ 200 cm.

2.3.3 PLINTOSSOLOS ARGILÚVICOS Eutróficos arênicos

Soils with a sandy texture from the surface to a depth of ≥ 50 cm and≤100 cm.

2.3.4 PLINTOSSOLOS ARGILÚVICOS Eutróficos espessos

Soils with a sandy loam or finer texture in one or more horizons from the soil surface to the top of the plinthic horizon, which occurs at depths of > 100 cm and ≤ 200 cm.

2.3.5 PLINTOSSOLOS ARGILÚVICOS Eutróficos abrúpticos

Solis with an abrupt textural change.

2.3.6 PLINTOSSOLOS ARGILÚVICOS Eutróficos gleissólicos

Soils with a gley horizon within the first 50 cm or between 50 cm and 100 cm, provided they are preceded by predominantly grayish horizons.

2.3.7 PLINTOSSOLOS ARGILÚVICOS Eutróficos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons within 150 cm from the soil surface.

2.3.8 PLINTOSSOLOS ARGILÚVICOS Eutróficos típicos

Other soils that do not fit in the previous classes.

3.1 PLINTOSSOLOS HÁPLICOS Ácricos

3.1.1 PLINTOSSOLOS HÁPLICOS Ácricos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.1.2 PLINTOSSOLOS HÁPLICOS Ácricos espessos

Soils with a sandy loam or finer texture in one or more horizons from the soil surface to the top of the plinthic horizon, which occurs at a depth of > 100 cm and ≤ 200 cm.

3.1.3 PLINTOSSOLOS HÁPLICOS Ácricos gleissólicos húmicos

Soils with a humic A horizon and gley horizon within the first 50 cm or between 50 cm and 100 cm, provided they are preceded by predominantly grayish horizons (Reunião..., 2017, profile RO-15).

3.1.4 PLINTOSSOLOS HÁPLICOS Ácricos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons within 150 cm from the soil surface.

3.1.5 PLINTOSSOLOS HÁPLICOS Ácricos húmicos

Solis with a humic A horizon.

3.1.6 PLINTOSSOLOS HÁPLICOS Ácricos típicos

Other soils that do not fit in the previous classes.

3.2 PLINTOSSOLOS HÁPLICOS Alumínicos

3.2.1 PLINTOSSOLOS HÁPLICOS Alumínicos fragmentários

Soils with a fragmentary lithic contact within 50 cm from the soil surface.

3.2.2 PLINTOSSOLOS HÁPLICOS Alumínicos líticos

Soils with lithic contact within 50 cm from the soil surface.

3.2.3 PLINTOSSOLOS HÁPLICOS Alumínicos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.2.4 PLINTOSSOLOS HÁPLICOS Alumínicos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.2.5 PLINTOSSOLOS HÁPLICOS Alumínicos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.2.6 PLINTOSSOLOS HÁPLICOS Alumínicos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons within 150 cm from the soil surface.

3.2.7 PLINTOSSOLOS HÁPLICOS Alumínicos húmicos

Solis with a humic A horizon.

3.2.8 PLINTOSSOLOS HÁPLICOS Alumínicos típicos

Other soils that do not fit in the previous classes.

3.3 PLINTOSSOLOS HÁPLICOS Distróficos

3.3.1 PLINTOSSOLOS HÁPLICOS Distróficos fragmentários

Soils with a fragmentary lithic contact within 50 cm from the soil surface.

3.3.2 PLINTOSSOLOS HÁPLICOS Distróficos líticos

Soils with a lithic contact within 50 cm from the soil surface.

3.3.3 PLINTOSSOLOS HÁPLICOS Distróficos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.3.4 PLINTOSSOLOS HÁPLICOS Distróficos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.3.5 PLINTOSSOLOS HÁPLICOS Distróficos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.3.6 PLINTOSSOLOS HÁPLICOS Distróficos espessos

Soils with a sandy loam or finer texture in one or more horizons from the soil surface to the top of the plinthic horizon, which occurs at a depth of > 100 cm and ≤ 200 cm.

3.3.7 PLINTOSSOLOS HÁPLICOS Distróficos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons within 150 cm from the soil surface.

3.3.8 PLINTOSSOLOS HÁPLICOS Distróficos húmicos

Soils with a humic A horizon.

3.3.9 PLINTOSSOLOS HÁPLICOS Distróficos típicos

Other soils that do not fit in the previous classes.

3.4 PLINTOSSOLOS HÁPLICOS Eutróficos

3.4.1 PLINTOSSOLOS HÁPLICOS Eutróficos fragmentários

Soils with a fragmentary lithic contact within 50 cm from the soil surface.

3.4.2 PLINTOSSOLOS HÁPLICOS Eutróficos líticos

Soils with a lithic contact within 50 cm from the soil surface.

3.4.3 PLINTOSSOLOS HÁPLICOS Eutróficos leptofragmentários

Soils with a fragmentary lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.4.4 PLINTOSSOLOS HÁPLICOS Eutróficos lépticos

Soils with a lithic contact at a depth of > 50 cm and ≤ 100 cm from the soil surface.

3.4.5 PLINTOSSOLOS HÁPLICOS Eutróficos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.4.6 PLINTOSSOLOS HÁPLICOS Eutróficos espessos

Soils with a sandy loam or finer texture in one or more horizons from the soil surface to the top of the plinthic horizon, which occurs at a depth of > 100 cm and ≤ 200 cm.

3.4.7 PLINTOSSOLOS HÁPLICOS Eutróficos petroplínticos

Soils with concretionary and/or lithoplinthic qualifiers or concretionary and/or lithoplinthic horizons within 150 cm from the soil surface.

3.4.8 PLINTOSSOLOS HÁPLICOS Eutróficos típicos

Other soils that do not fit in the previous classes.

Chapter 17

Vertissolos

Vertissolos are soils composed of mineral material with a vertic horizon that begins within 100 cm from the surface and with an insufficient textural ratio to characterize a textural B horizon. In addition, they must meet the following requirements:

Clay content, after mixture and homogenization of the soil material, in the upper 20 cm, of ≥ 300 g kg⁻¹ soil;

Vertical cracks in the dry period at least 1 cm wide, starting at the soil surface and reaching a depth of ≥ 50 cm, except in the case of shallow soils, with a depth of ≥ 30 cm;

Absence of material with a fragmentary lithic or lithic contact, petrocalcic horizon or duripan within the first 30 cm from the soil surface;

In irrigated or poorly drained areas (without apparent cracks), the coefficient of linear expansion (COLE) must be ≥ 0.06 or the linear extensibility must be ≥ 6 cm; and

Absence of any type of diagnostic B horizon above the vertic horizon.

Classes of the 2nd categorical level (suborders)

1 VERTISSOLOS HIDROMÓRFICOS

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Soils with a gley horizon within the first 50 cm or between 50 cm and 100 cm, provided they are preceded by predominantly grayish horizons.

2 VERTISSOLOS EBÂNICOS

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Soils with an ebanic qualifier in most of the B and/or C horizons (including BA or CA) within 100 cm from the soil surface.

3 VERTISSOLOS HÁPLICOS

(Click to enlarge)

Other soils that do not fit in the previous classes.

Classes of the 3rd categorical level (great groups)

1 VERTISSOLOS HIDROMÓRFICOS

1.1 VERTISSOLOS HIDROMÓRFICOS Carbonáticos

Soils with a carbonatic qualifier in one or more horizons or layers or with a calcic horizon, both within 100 cm from the soil surface.

1.2 VERTISSOLOS HIDROMÓRFICOS Sódicos

Soils with a sodic qualifier in one or more horizons or layers within 100 cm from the soil surface.

1.3 VERTISSOLOS HIDROMÓRFICOS Sálicos

Soils with a salic qualifier in one or more horizons or layers within 100 cm from the soil surface (Jacomine et al., 1971, p. 311, profile 38).

1.4 VERTISSOLOS HIDROMÓRFICOS Órticos

Other soils that do not fit in the previous classes.

2 VERTISSOLOS EBÂNICOS

2.1 VERTISSOLOS EBÂNICOS Carbonáticos

Soils with a carbonatic qualifier in one or more horizons or layers or with a calcic horizon, both within 100 cm from the soil surface (Freitas et al., 1971, p. 560, profile 111).

2.2 VERTISSOLOS EBÂNICOS Sódicos

Soils with a sodic qualifier in one or more horizons or layers within 100 cm from the soil surface.

2.3 VERTISSOLOS EBÂNICOS Órticos

Other soils that do not fit in the previous classes.

3 VERTISSOLOS HÁPLICOS

3.1 VERTISSOLOS HÁPLICOS Carbonáticos

Soils with a carbonatic qualifier in one or more horizons or layers or with calcic horizon, both within 100 cm from the soil surface.

3.2 VERTISSOLOS HÁPLICOS Sódicos

Soils with a sodic qualifier in one or more horizons or layers within 100 cm from the soil surface.

3.3 VERTISSOLOS HÁPLICOS Sálicos

Soils with a salic qualifier in one or more horizons or layers within 100 cm from the soil surface

3.4 VERTISSOLOS HÁPLICOS Órticos

Other soils that do not fit in the previous classes.

Classes of the 4th categorical level (subgroups)

1.1 VERTISSOLOS HIDROMÓRFICOS Carbonáticos

1.1.1 VERTISSOLOS HIDROMÓRFICOS Carbonáticos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

1.1.2 VERTISSOLOS HIDROMÓRFICOS Carbonáticos típicos

Other soils that do not fit in the previous class.

1.2 VERTISSOLOS HIDROMÓRFICOS Sódicos

1.2.1 VERTISSOLOS HIDROMÓRFICOS Sódicos salinos

Soils with a saline qualifier in one or more horizons or layers within 150 cm from the soil surface (Jacomine et al., 1977-1979, v. 2, p. 842, profile 261).

1.2.2 VERTISSOLOS HIDROMÓRFICOS Sódicos típicos

Other soils that do not fit in the previous class (Jacomine et al., 1975a, p. 343, profile 57).

1.3 VERTISSOLOS HIDROMÓRFICOS Sálicos

1.3.1 VERTISSOLOS HIDROMÓRFICOS Sálicos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

1.3.2 VERTISSOLOS HIDROMÓRFICOS Sálicos típicos

Other soils that do not fit in the previous class (Jacomine et al., 1971, p. 311, profile 38; Jacomine, 1986a, v. 2, p. 581, profile 132).

1.4 VERTISSOLOS HIDROMÓRFICOS Órticos

1.4.1 VERTISSOLOS HIDROMÓRFICOS Órticos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

1.4.2 VERTISSOLOS HIDROMÓRFICOS Órticos chernossólicos

Soils with a chernozemic A horizon.

1.4.3 VERTISSOLOS HIDROMÓRFICOS Órticos típicos

Other soils that do not fit in the previous classes.

2.1 VERTISSOLOS EBÂNICOS Carbonáticos

2.1.1 VERTISSOLOS EBÂNICOS Carbonáticos chernossólicos

Soils with a chernozemic A horizon.

2.1.2 VERTISSOLOS EBÂNICOS Carbonáticos típicos

Other soils that do not fit in the previous class.

2.2 VERTISSOLOS EBÂNICOS Sódicos

2.2.1 VERTISSOLOS EBÂNICOS Sódicos salinos

Soils with a saline qualifier in one or more horizons or layers within 150 cm from the soil surface (Jacomine et al., 1977-1979, v. 2, p. 842, profile 261).

2.2.2 VERTISSOLOS EBÂNICOS Sódicos típicos

Other soils that do not fit in the previous class.

2.3 VERTISSOLOS EBÂNICOS Órticos

2.3.1 VERTISSOLOS EBÂNICOS Órticos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface (Jacomine et al., 1972-1973, v. 2, p. 246, profile 77).

2.3.2 VERTISSOLOS EBÂNICOS Órticos gleissólicos

Soils with a gley horizon within 100 cm from the soil surface.

2.3.3 VERTISSOLOS EBÂNICOS Órticos chernossólicos

Soils with a chernozemic A horizon.

2.3.4 VERTISSOLOS EBÂNICOS Órticos típicos

Other soils that do not fit in the previous classes (Jacomine, 1986b, v. 2, p. 456, profile 98).

3.1 VERTISSOLOS HÁPLICOS Carbonáticos

3.1.1 VERTISSOLOS HÁPLICOS Carbonáticos fragmentários

Soils with a fragmentary lithic contact within 50 cm from the soil surface.

3.1.2 VERTISSOLOS HÁPLICOS Carbonáticos líticos

Soils with a lithic contact within 50 cm from the soil surface.

3.1.3 VERTISSOLOS HÁPLICOS Carbonáticos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.1.4 VERTISSOLOS HÁPLICOS Carbonáticos gleissólicos

Soils with a gley horizon within 100 cm from the soil surface.

3.1.5 VERTISSOLOS HÁPLICOS Carbonáticos chernossólicos

Soils with a chernozemic A horizon.

3.1.6 VERTISSOLOS HÁPLICOS Carbonáticos típicos

Other soils that do not fit in the previous classes.

3.2 VERTISSOLOS HÁPLICOS Sódicos

3.2.1 VERTISSOLOS HÁPLICOS Sódicos fragmentários

Soils with a fragmentary lithic contact within 50 cm from the soil surface.

3.2.2 VERTISSOLOS HÁPLICOS Sódicos líticos

Soils with a lithic contact within 50 cm from the soil surface.

3.2.3 VERTISSOLOS HÁPLICOS Sódicos salinos

Soils with a saline qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.2.4 VERTISSOLOS HÁPLICOS Sódicos gleissólicos

Soils with a gley horizon within 100 cm from the soil surface.

3.2.5 VERTISSOLOS HÁPLICOS Sódicos típicos

Other soils that do not fit in the previous classes.

3.3 VERTISSOLOS HÁPLICOS Sálicos

3.3.1 VERTISSOLOS HÁPLICOS Sálicos fragmentários

Soils with a fragmentary lithic contact within 50 cm from the soil surface.

3.3.2 VERTISSOLOS HÁPLICOS Sálicos líticos

Soils with a lithic contact within 50 cm from the soil surface.

3.3.3 VERTISSOLOS HÁPLICOS Sálicos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.3.4 VERTISSOLOS HÁPLICOS Sálicos gleissólicos

Soils with a gley horizon within 100 cm from the soil surface.

3.3.5 VERTISSOLOS HÁPLICOS Sálicos típicos

Other soils that do not fit in the previous classes.

3.4 VERTISSOLOS HÁPLICOS Órticos

3.4.1 VERTISSOLOS HÁPLICOS Órticos fragmentários

Soils with a fragmentary lithic contact within 50 cm from the soil surface.

3.4.2 VERTISSOLOS HÁPLICOS Órticos líticos

Soils with a lithic contact within 50 cm from the soil surface.

3.4.3 VERTISSOLOS HÁPLICOS Órticos salinos

Soils with a saline qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.4.4 VERTISSOLOS HÁPLICOS Órticos hipocarbonáticos solódicos

Soils with solodic and hypocarbonatic qualifiers, both in one or more horizons or layers within 150 cm from the soil surface (Romero et al., 2009, profile 5).

3.4.5 VERTISSOLOS HÁPLICOS Órticos hipocarbonáticos chernossólicos

Soils with a chernozemic A horizon and a hypocarbonatic qualifier in one or more horizons or layers within 150 cm from the soil surface (Reunião..., 2010a, profile AC - P07).

3.4.6 VERTISSOLOS HÁPLICOS Órticos solódicos

Soils with a solodic qualifier in one or more horizons or layers within 150 cm from the soil surface.

3.4.7 VERTISSOLOS HÁPLICOS Órticos gleissólicos

Soils with a gley horizon within 100 cm from the soil surface.

3.4.8 VERTISSOLOS HÁPLICOS Órticos chernossólicos.

Soils with a chernozemic A horizon.

3.4.9 VERTISSOLOS HÁPLICOS Órticos típicos

Other soils that do not fit in the previous classes (Reunião..., 1998, p. 68, profile 11).

Chapter 18

Provisional definitions for the 5th and 6th categorical levels (families and series)

The 5th and 6th categorical levels are used for pragmatic applications. The differential characteristics and properties related to land use and soil management for various purposes should be prioritized for classification at these two categorical levels.

Classes of the 5th categorical level (families)

Listed below are the characteristics/properties to classify soils at the 5th categorical level, to be used when pertinent, i.e., if required by the classes of the 4th level, be it by complementing information of the higher categorical levels, be it by adding new information relevant for utilitarian purposes.

It is worth emphasizing that the use of the classes at the 5th categorical level is not mandatory and that not all characteristics/properties are applicable to all soil classes. Their use should be defined by the peculiarities of the soil surveys whenever data are available or the analyses are necessary. In the soil classification, the characteristics identifying the 5th categorical level should be added after the designation of the 4th categorical level and separated from the 4th level properties and each other by a comma.

Mineral soils

For soils of mineral constitution, the following differential characteristics are used:

Textural group

Textural subgroup.

Gravel distribution in the profile.

Skeletal soil constitution.

Type of diagnostic surface horizon.

Prefixes epi-, meso- and endo-.

Base saturation.

Aluminum saturation.

Mineralogy.

Subgroup of the clay fraction activity.

Iron oxide content.

Andic properties.

Textural group

The textural group should be generally used in soil surveys or related work to differentiate all soil classes at the 5th categorical level (see Chapter 1, Textural grouping), except in the case of Neossolos Quartzarênicos. If more detailed information is required, the textural subgroups (described below) can be used instead of the groups.

Textural subgroup⁴¹

When more detailed information is required, the textural subgroup is used instead of the textural group.

A textural subgroup can be used instead of the textural group in the classes of Espodossolos, Latossolos psamíticos, Neossolos Flúvicos Psamíticos, Neossolos Regolíticos, Neossolos Quartzarênicos, as well as for the classes arênicos and espessarênicos of the 4th categorical level (used for Argissolos, Luvissolos, Planossolos and Plintossolos).

It can also be used for soil classes with a sandy and/or loamy texture (in simple, binary or ternary notation).

Textural subgroups are divided according to the following criteria (guide in Figure 1):

Sand texture – comprises the textural class sand.

Loamy sand texture – comprises the textural class loamy sand.

Sandy loam texture – comprises the textural class sandy loam, with > 520 g kg⁻¹ sand.

Clay loam texture – comprises the textural class sandy clay loam.

Silty loam texture – particle size composition with < 350 g kg⁻¹ clay and > 150 g kg⁻¹ sand, excluding the textural classes sand, loamy sand, sandy clay loam and sandy loam, with > 520 g kg⁻¹ sand.

Silty texture – particle size composition with < 350 g kg⁻¹ clay and < 150 g kg⁻¹ sand.

Clay texture – particle size composition with ≥ 350 g kg⁻¹ to ≤ 600 g kg⁻¹ clay.

Very fine clayey texture – particle size composition with > 600 g kg⁻¹ clay.

Figure 1. Guide of textural class subgroups.

In soils with different classes of textural subgroups in depth, the control section that defines the soil class at the categorical level of order should be considered, admitting at most a ternary notation.

Gravel distribution in the profile

The gravel distribution in the profile should be taken into account for all classes with a gravel content of > 80 g kg⁻¹, complementary to the textural group or subgroup.

The following classes should be used: slightly gravelly, gravelly and very gravelly, as defined in Chapter 1 (Gravel distribution in the profile).

Skeletal soil constitution

The term "skeletal" should be used immediately after the textural group or subgroup, for example, "loamy skeletal texture", according to the criteria listed in Chapter 1 (Skeletal soil constitution).

Type of diagnostic surface horizon

Diagnostic surface horizons should be used for all soil classes, except when already considered at a higher categorical level.

See definitions in Chapter 2 (Diagnostic surface horizons).

Prefixes epi-, meso- and endo-

The prefixes epi-, meso- and endo- must be added to indicate the depth of occurrence of some attributes, except when already indicated at a higher categorical level.

The prefix epi- is used to designate an attribute that occurs in the surface and/or within the soil, to a maximum depth of 50 cm. Examples: "epiconcretionary", "epilithoplinthic", "episaprolithic", "epialic", "epieutrophic".

The prefix meso- is used to designate an attribute within 50 to 100 cm from the soil surface. The occurrence in the section can be continuous or interspersed, but should be > 50 cm below the soil surface. Examples: "mesoconcretionary", "mesolithoplinthic", "mesosaprolithic", "mesoaluminic", "mesocarbonatic", "mesosalic", "mesosaline", "mesosodic", "mesothiomorphic".

The prefix endo- is used to indicate an attribute that occurs below > 100 cm. The respective attribute can occur in a continuous section or interspersed, but deeper than 100 cm below the soil surface. Examples: "endoconcretionary", "endolithoplinthic", "endosaprolithic", "endolithic", "endoaluminic", "endocarbonatic", "endosalic", "endosaline", " endosodic", "endothiomorphic".

In view of the peculiarities of the study area, land use and soil management, other soil attributes may be incorporated and/or the control section proposed here may be adapted. In these cases, the changes should be described in the study methodology.

Base saturation

Base saturation is used for all soil classes, except when already considered at a higher categorical level. Wherever appropriate, it is advised to use the prefixes epi-, meso- and endo-, as defined above.

Aluminum saturation

The term "alic" is used when the aluminum saturation [(100 Al⁺³/ (S + Al⁺³)] is ≥ 50% and the extractable aluminum content > 0.5 cmolc kg⁻¹ soil.

The term "alic" should be applied to designate the class whose aluminic qualifier was not expressed at a higher categorical level. Wherever appropriate, it is advised to use the prefixes epi-, meso- and endo-, as defined above.

Mineralogy

Mineralogy corresponds to the characterization and quantification of the mineralogical composition of the sand (coarse and fine), silt and clay fractions.

The mineralogical characterization is defined by the predominance of the mineral constituents of the soil, based on the terms and definitions below:

In the sand fraction (diameter ≥ 0.05–2 mm), mainly of soils with a loamy and sandy texture, if at least semiquantitative mineralogical data are available, the following terms may be used to emphasize information about predominance of easily or not easily alterable minerals.

Micaceous – presence of mica in quantities of ≥ 15% of the soil volume.

Amphibolitic – presence of amphiboles in quantities of ≥ 15% of the soil volume.

Feldspathic – presence of feldspars in quantities of ≥ 15% of the soil volume.

Thus, the mineralogical qualifier should be set in parentheses before the textural group or subgroup, whenever pertinent, for example: (micaceous) loamy texture, (feldspathic) loamy /clayey texture.

A mineralogical qualifier can be used for Cambissolos, Chernossolos, Gleissolos, Luvissolos, Neossolos (excepting Neossolos Quartzarênicos), Nitossolos, Planossolos, Plintossolos and Vertissolos.

The following qualifiers should be used for the < 0.002 mm fractions (clay minerals) of Latossolos, if the information is available:

Kaolinitic – with predominance of clay minerals of the kaolinite group. The following reference values of Ki and Kr (Resende; Santana, 1988) are used for the classes:

Kaolinitic – Ki > 0.75 and Kr > 0.75.

Oxidic-kaolinitic – Ki > 0.75 and Kr ≤ 0.75.

Gibbsitic – with predominance of gibbsite. The following Ki and Kr values are used as reference (Kämpf et al., 1988; Ker, 1995):

Oxidic-gibbsitic – Ki and Kr ≤ 0.75 ≤ 0.75.

Oxidic – with predominance of iron and aluminum oxides (Kr ≤ 0.75), which can be subdivided in hemathitic and goethitic.

If at least semiquantitative data about clay mineralogy are available, the terms above may also be used for Argissolos, Cambissolos and Plintossolos.

Subgroup of clay fraction activity⁴²

This criterion can be applied to classes in which the subsequent separation of the clay activity is relevant, even to those which, by definition, have a low (Latossolos) or high (Chernossolos, Luvissolos and Vertissolos) activity clay.

The following classes should be used:

Very low activity clay (Tvl): < 8 cmolc kg⁻¹ clay.

Moderately low activity clay (Tml): between 8 cmolc kg⁻¹ and < 17 cmolc kg⁻¹ clay.

Medium activity clay (Tm): between 17 cmolc kg⁻¹ and < 27 cmolc kg⁻¹ clay.

Moderately high activity clay (Tmh): between 27 cmolc kg⁻¹ and < 40 cmolc kg⁻¹ clay.

Very high activity clay (Tvh): ≥ 40 cmolc kg⁻¹ clay.

This characteristic should be considered in the major part of the B horizon (including BA) or in the C horizon (including CA), when there is no B, within the control section that defines the class. The appropriate symbol to define the clay activity subgroup should be used in the soil classification. This criterion is not applied to soils of the texture classes sand and loamy sand.

Iron oxide content

The iron oxide content must be applied in the designation of classes in which this qualifier was not considered previously for separation at a higher categorical level. Therefore, it can be used for the classes Argissolos, Cambissolos, Chernossolos, Latossolos, Neossolos Litólicos, Neossolos Regolíticos, Nitossolos and Plintossolos.

See definitions in Chapter 1 (Iron oxide content).

Andic properties

The term "andic" should be applied in the designation of the classes in which this property occurs. It can be used for Cambissolos Hísticos and Organossolos Fólicos.

See definitions in Chapter 1 (Andic properties).

Organossolos

These soils are discriminated by the nature and texture of the material underlying the organic material such as sand, silt, clay and origin of sediments. If the underlying material within the control section has a mineral constitution, the differential characteristics of mineral soils can be applied.

At this taxonomic level, the Organossolos with > 100 cm organic material from the surface are also worth mentioning.

Another relevant characteristic is the presence of branches and parts of tree trunks in the soil profile, resulting in a high subsidence potential and in mechanical barriers against agricultural practices. In this case, the proportion of this material must be identified in relation to the volume of the horizon of occurrence, distinguishing the classes woody, very woody and extremely woody, as similarly used to characterize stoniness classes.

Classes of the 6th categorical level (series)

The 6th categorical level is still being discussed. The characteristics/properties that will be applied in the soil classification must be directly related to plant growth, concerning mainly the root system development, the soil-water-plant relationships and relevant properties for interpretations in the fields of geotechnics and engineering. Differences between characteristics and properties within a family that affect land use and management should be taken into consideration in the determination of the 6th level, to facilitate quantitative interpretations for these purposes, be it for agricultural or non-agricultural uses.

Although conceptually still undefined, some characteristics/properties are suggested below to differentiate the classes at the 6th categorical level.

Mineral soils

In soils with a mineral constitution, the following characteristics and properties can be used for the 6th level:

Type, thickness and sequence of the horizons.

Structure.

Color, mottles.

Profile internal drainage (Appendix B).

Texture (textural class of surface and subsurface horizons).

Consistence.

Special pedogenetic characteristics or properties defined by land use, such as compaction and dense layers of natural origin.

Organic matter content.

Percentage of rock fragments in the soil.

Proportional relationship between certain components (for example, proportion of coarse to fine sand, of very fine to fine sand), determining differences in porosity and water retention.

Attributes related to the availability of air and water in the soil ⁴³.

Organossolos⁴⁴

In the establishment and definition of the lower categorical levels of the order of Organossolos, mainly, it is suggested to consider the thickness, classes of decomposition degree and fiber content (Appendix D) of the organic horizons and/or layers, the presence of groundwater in relation to the soil surface, depth of occurrence and thickness of the mineral substrate in the control section of the class, and the abundance of occurrence of plant parts or fragments (> 2 cm). Valladares et al. (2003) and Fontana et al. (2011) suggested attributes related to the distribution of humic fractions of the soil organic matter as differential characteristics of Organossolos.

For this class, it is important to develop methods and identify attributes that allow an evaluation of the subsidence potential of soil under agricultural management or for purposes of engineering and geotechnics, in particular due to the practice of draining.

Notes

(41) In the validation phase.

(42) In the validation phase.

(43) Classes based on physical-hydric soil attributes, with specific nomenclature, were proposed (Ottoni Filho, 2003; Macedo et al., 2005).

(44) Classes of Organossolos, based on the distribution of the soil organic matter fractions: humic acid, fulvic acid and humin, were proposed (Valladares, 2003).

Chapter 19

Distinctive criteria of phases of mapping units

The phases are used for an even more homogeneous subdivision of the soil classes, and they reflect conditions that directly or indirectly influence the soil pattern and qualities.

The phases most commonly used in soil surveys in Brazil are, according to Carvalho et al. (1988) and IBGE (2015):

Soil phases and conditions indicated by the primary vegetation

It is known that the primary vegetation is strongly related to climate and soil properties. Comparisons between climate and phytogeographic divisions (hydric and thermal indices versus vegetation types) reveal the existence of relations among vegetation and certain soil-climatic conditions, in particular with regard to the hydric and thermal regimes and natural soil fertility (eutrophy and oligotrophy).

In view of the lack of soil climate data, mainly of hydric and thermal data, to make possible inferences about seasonal variations of soil moisture, the vegetation phases are used, since the primary vegetation reflects the predominant climatic differences associated with the diverse soil conditions. Admittedly, apart from the pedogenetic significance, these distinctions result in broad ecological implications, allowing for the establishment of relationships between soil units and their agricultural and ecological suitability, thereby increasing the practical utility of soil surveys.

Currently, Embrapa Soils recognizes the following vegetation types, which indicate hydric and thermal conditions and oligotrophy of soils:

Equatorial forest

Perhumid evergreen rain forest.

Evergreen rain forest45 46.

Semi-evergreen45 46.

Semideciduous45 .

Hydrophilous floodplain.

Hygrophilous floodplain.

Tropical forest

Perhumid evergreen rain forest⁴⁷.

Evergreen rain forest⁴⁷.

Semi-evergreen⁴⁷.

Deciduous⁴⁷.

Hydrophilous floodplain.

Hygrophilous floodplain⁴⁸.

Subtropical forest

Perhumid evergreen rain forest⁴⁶.

Evergreen rain forest⁴⁶.

Semi-evergreen.

Semideciduous (tree-shrub formation under subhumid conditions).

Hydrophilous floodplain.

Hygrophilous floodplain.

Restinga vegetation (sand bars and coastal sand plains psammophilous vegetation)

Non-hydrophilous restinga forest.

Hydrophilous restinga forest.

Shrub restinga and grassland restinga.

Cerrado vegetation (Brazilian savannah)

Semi-evergreen equatorial cerrado.

Equatorial cerrado grassland.

Equatorial palm swamp.

Semi-evergreen tropical cerrado.

Semideciduous tropical cerrado.

Deciduous tropical cerrado.

Tropical cerrado grassland.

Semi-evergreen tropical woodland cerrado.

Semideciduous tropical woodland cerrado.

Tropical palm swamp.

Caatinga vegetation (deciduous thorn scrub-land)

Hypoxerophylous⁴⁹.

Hyperxerophilous.

Pantanal complex.

Grassland vegetation

Equatorial grassland⁵⁰.

Hydrophilic equatorial floodplain grassland.

Hygrophilous equatorial floodplain grassland.

Tropical grassland⁵⁰.

Hydrophilic tropical floodplain grassland.

Hygrophilous tropical floodplain grassland.

Subtropical perhumid grassland (high-montane vegetation).

Humid subtropical grassland.

Subhumid subtropical grassland.Hydrophilic subtropical floodplain grassland.

Hygrophilous subtropical floodplain grassland.

Xerophytic grassland.

Hydrophilic grassland of sources/springs.

Other formations

Riparian forest of carnauba palm.

Beach and dune formations.

Halophytic formations.

Mangrove.

Rupicolous formations.

Relief phases

These phases are characterized by the slope gradient and length and shape of the terrain surface, affecting the geomorphical (topographical) forms in the soil unit areas.

The distinctions are used to provide information about the feasibility of agricultural practices, especially motorized equipment, and inferences about soil erosion susceptibility.

The following relief classes are recognized:

Nearly level (flat) – leveled or horizontal surface topography, with only minor unevenness, with slopes varying from 0% to 3%.

Gently undulating – slightly hilly surface topography, constituted by a range of hillocks and/or knolls (elevations of relative altitudes of ≤ 50 m and 50-100 m, respectively), with gentle slopes, predominantly from 3% to 8%.

Undulating – hilly surface topography, consisting of a range of hillocks and/or knolls with moderate slopes, predominantly from 8% to 20%.

Strongly undulating – very hilly surface topography, formed by knolls and/or hills (elevations of relative altitudes of 50–100 m and 100–200 m, respectively) and rarely hillocks, with steep slopes, predominantly from 20% to 45%.

Mountainous – steep surface topography, with predominance of rugged shapes, usually consisting of hills, mountains, mountain massifs and mountainous chains, with steep and very steep slopes, predominantly from 45% to 75%.

Rugged – areas with predominance of abrupt shapes, including very steep hillsides and scarps, such as: bluffs, precipices (so-called "itaimbés"), scarp slopes of cuestas, cliffs, very steep slopes, usually with declivity > 75%.

Stony phases

These phases characterize areas with pronounced quantities of gravel (diameter 2–20 cm) and boulders (diameter 20–100 cm) in the soil surface or subsurface, interfering with land use, especially with regard to mechanical practices and tillage for agriculture, i.e. containing 3% or more of the said macroclastic material. This quantification comprises the stony classes called stony, very stony and extremely stony, as indicated in item 2.7 of Reunião... (1979b) and by Santos et al. (2015).

Different stony phases are identified, according to the position of occurrence of gravel and boulders, to a soil depth of 150 cm or to a lithic or fragmentary lithic contact occurring to a depth of < 150 cm. They are divided into:

Stony phase

The soil contains gravel and/or boulders along the entire profile or on the surface of the upper horizon(s) and to a depth of > 40 cm.

Surface stony phase

The soil contains gravel and/or boulders at the surface and/or within the soil to a maximum depth of 40 cm. Soils with a stony pavement that cannot be easily removed are also included in this phase.

Subsurface stony phase

The soil contains gravel and/or boulders at depths > 40 cm. This phase includes soils with an interspersed stony section as well as those with continuous stoniness in depth, but at depths of > 40 cm below the soil surface.

Rocky phases

Rocky phases refer to the exposure, at the surface or in the soil mass, of rocky substrate, rock slabs, areas of very shallow soil on top of the rock and/or predominance of boulders with an average diameter of > 100 cm in such quantities that the use of machinery for agriculture becomes impracticable.

The rocky phase will be identified in soil(s) with the following rocky classes: rocky, very rocky and extremely rocky, according to the description in item 2.8 of Reunião... (1979b) and by Santos et al. (2015).

Occasionally, it is necessary to combine the stony with the rocky classes. In these cases, the influence of both conditions on land use has to be considered.

Eroded phase

In soils with a strong, very strong and extremely strong erosion class, the eroded phase will be identified according to the description in item 2.6 of Reunião... (1979b) and Santos et al. (2015).

Substrate phase

The substrate phase refers to the nature of the rock that constitutes the substrate at the profile location. It is used for the classes Cambissolos (except Cambissolos Flúvicos), Neossolos Litólicos and Neossolos Regolíticos to complement information with relation to the attributes inherited from the parent material. This phase is also of interest for geotechnical soil uses.

Notes

(45) Dicot-palm forest (babassu palm), when appropriate.

(46) Distinguish high-montane, when appropriate.

(47) Floodplain, when appropriate.

(48) In the case of "campinaranas" (white-sand forest), add specification.

(49) In the case of "grameal" (densely interweaved thin 4-8 m high shrubs), add specification.

(50) Distinguish high-montane, where appropriate.

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Appendices

Appendix A

Classes of soil depth

The soil depth classes are characterized by the terms "shallow", "fairly deep", "deep" and "very deep". This wording is used to designate conditions of soils in which a lithic or fragmentary lithic contact occurs within the limits specified in Table 1.

(To see the table as an image, click here).

Table 1. Classes of soil depth.

Class

Depth

Shallow

≤ 50 cm

Fairly deep

˃ 50 cm and ≤ 100 cm

Deep

˃ 100 cm and ≤ 200 cm

Very deep

˃ 200 cm

The terms used to describe the soil depth classes are designations applied to generalized descriptions of soils. Such designations shall not be used as qualifying in the differentiating characteristics of a taxon.

Appendix B

Drainage classes

The drainage classes refer to the quantity and speed at which the received water infiltrates into the soil and/or runs off, affecting the soil water conditions – the length of the period during which the soil remains moist, wet or soaked.

According to the criteria derived from Soil Survey Manual (United States, 1951; 1993) and implemented in Súmula... (Reunião Técnica..., 1979) and in the Manual de Descrição e Coleta de Solo no Campo (Santos et al., 2015), the distinguished drainage classes are assigned according to the following specifications:

Excessively drained – water is removed from the soil very quickly; the soil material has high porosity and permeability, with a commonly sandy soil texture in this drainage class.

Strongly drained – water is removed quickly from the profile; highly porous and permeable soils, as those of loamy and sandy texture, belong to this drainage class.

Intensely drained – water is removed quickly from the profile; the soils of this drainage class usually have a loamy or clayey texture, but are always very porous and permeable.

Well drained – water is readily removed from the soil, but not quickly; the soils of this drainage class commonly have a loamy or clayey texture, normally without mottles due to oxidation-reduction processes. However, if present, the mottles occur in depth, at > 150 cm below the soil surface and also at > 30 cm below the top of the B or C, if there is no B horizon.

Moderately drained –water is drained from the soil somewhat slowly, so that the profile remains moist for a short but significant part of the year. The soils of this drainage class commonly have a slowly permeable layer in the solum or immediately below it. The water table is immediately below the solum or affects the lower part of the B horizon, by adding water by means of internal lateral translocation, or some combination of these conditions. These soils may contain some mottle, due to oxidation and reduction processes at the lower part of the B horizon or on its top, associated with the textural difference between the A and B horizons, which may result in the manifestation of redoxic qualifier.

Imperfectly drained – water is drained slowly from the soil, which remains moist during a significant period, but not for most part of the year. The soils of this drainage class commonly have a slowly permeable layer in the solum, a high water table, water input from internal lateral translocation, or some combination of these conditions. Usually they have some mottles, due to oxidation and reduction processes in the profile, with visible signs of gleization in the deeper horizons.

Poorly drained – water is drained from the profile so slowly that it remains moist for a large part of the year. The water table is commonly levelled with or near the surface during a considerable part of the year. The conditions of poor drainage are due to a high water table, slowly permeable layer in the profile, water input from internal lateral translocation, or some combination of these conditions. The occurrence of mottles and gleization characteristics in the profile are frequent..

Very poorly drained – water is removed from the profile so slowly that the water table remains on the surface or near it during the greater part of the year. Soils of this drainage classes usually occupy flat areas or depressions, with frequent water stagnation. In these soils, characteristics of gleization are common and/or at least superficial accumulation of organic matter, commonly with a histic horizon.

Appendix C

Classes of soil reaction

These classes differentiate the acidity or alkalinity status of the soil material.

Based on the criteria adopted by Embrapa Soils, the different classes are characterized according to the specifications in Table 1.

(To see the table as an image, click here).

Table 1. Specifications of soil reaction classes.

Class

pH (soil/water 1:2.5)

Extremely acidic

< 4.3

Strongly acidic

4.3 – 5.3

Moderately acidic

5.4 – 6.5

Practically neutral

6.6 – 7.3

Moderately alkaline

7.4 – 8.3

Strongly alkaline

˃ 8.3

Appendix D

Methods of soil analyses adopted by Embrapa Soils

The analytical methods described below are based on the Manual de Métodos de Análise de Solo (Claessen, 1997; Teixeira et al., 2017).

The analyses are performed in the air-dried fine earth fraction (ADFE) of the prepared soil samples. However, the results for the samples are multiplied by the respective moisture factors to express the values at 105 °C (oven-dried fine earth – ODFE). Exceptions to the determinations and expression of the results are: pebbles and gravels; fine earth; bulk density; porosity calculation; electrical conductivity in the saturation extract; mineralogy of pebbles, gravel, coarse sand, fine sand and clay; CaCO₃ equivalent, when determined in the total sample (fine earth + gravels + pebbles); organic carbon, when determined in the total sample, indicated for horizons with organic constitution (O, H); and, occasionally, pH of material under natural moisture conditions, without desiccation, indicated for soils with the presence of tiomorphism.

Fraction > 2 mm (gravels and pebbles) and < 2 mm (fine earth) – prepared by drying of the total sample, crushing with a wooden mallet, sieving through sieve with round holes (diameter 2 mm); percentage by weight by gravimetric determination.

Particle-size composition of the fine earth (fraction < 2 mm) – dispersion with NaOH or, occasionally, sodium hexametaphosphate, high rotation shaking, sedimentation, clay determined by densimetry in the supernatant, coarse sand and fine sand separated by sieving and silt calculated by the difference; in the case of samples relatively rich in carbonates and soluble salts or organic matter, pre-treatments are applied.

Water-dispersible clay – procedures as in the above method, without the dispersing agent.

Flocculation degree – calculation based on the percentage of clay and of water-dispersible clay, determined as described above.

Bulk density – measured by the method of volumetric cylinder (100 cm³, of the graduated cylinder or of paraffin-coated clods.

Particle density – volumetric flask method with ethyl alcohol.

Total porosity – calculation based on the soil bulk and particle densities.

Soil water retention by the pressure plate apparatus and the Richards chamber methods – determined in samples collected in metallic cylinders, saturated by capillarity at ambient temperature, weighed and placed in a pressure plate apparatus or Richards chamber at different potentials.

pH in H₂O and in KCl 1 mol L⁻¹ – measurement through combined electrode immersed in soil:liquid suspension (water, KCl) at a ratio of 1:2.5.

Exchangeable cations – Al³⁺, Ca2+ and Mg2+ extracted with 1 mol L-1 KCl. Exchangeable Al3+ is determined volumetrically with a diluted NaOH solution. Ca²⁺ and Mg²⁺ are determined by complexometry or by atomic absorption spectrophotometry and K+ and Na+ extracted with Mehlich-1 solution and subsequent determination by flame spectrophotometry. When necessary in these measurements of extractable bases, the quantity contained in soluble salts ought to be deducted to obtain the values of exchangeable bases.

Sum of bases (S value) – calculation of the sum of exchangeable cations Ca²⁺, Mg²⁺, K⁺ and Na⁺ resulting from the previous determinations.

Potential acidity – extracted with calcium acetate buffered to pH 7.0 and volumetric determination with NaOH solution, with phenolphthalein as indicator.

Effective Cation Exchange Capacity – calculation of the sum of exchangeable cations (Ca²⁺ + Mg²⁺ + K⁺ + Na⁺ + Al³⁺) of the previous determinations.

Cation exchange capacity (T value) – determined by the sum of the S value and the potential acidity (H⁺ + Al³⁺) of the previous determinations.

Percentage of base saturation (V value) – calculation of the proportion of the total CEC (T value) on account of the exchangeable cations Ca²⁺ + Mg²⁺ + K⁺ + Na⁺.

Percentage of aluminum saturation (m) – calculation of the proportion of exchangeable aluminum in relation to concentrations of exchangeable cations (Ca²⁺ + Mg²⁺ + K⁺ + Na⁺ + Al³⁺) in the CEC of the soil, according to previous determinations, by the expression: [Al³⁺/Al3+ + S] x 100.

Percentage of sodium saturation – calculation of the proportion of exchangeable sodium in relation to the total cation exchange capacity, according to previous determinations.

Available phosphorus – extracted with Mehlich-1 extractor solution (0.05 mol L⁻¹ HCl + 0.0125 mol L-1 H₂SO₄) and determined by spectrophotometry.

Organic carbon – wet oxidation with 0.0667 mol L-1 K₂Cr₂O₇ and titration by 0.05 mol L-1 Fe(NH₄)₂(SO₄)₂.6H₂O, using diphenylamine as indicator.

Total nitrogen (Kjeldahl method) – the nitrogen of the organic matter is mineralized to ammonia (NH₄⁺) by oxidation with sulfuric acid at high temperature, in the presence of catalysts.

Sulfuric acid digestion – boiling of the fine earth fraction with 1:1 diluted H₂SO4 solution for: 1) iron⁵¹ and aluminum⁵¹ extraction from the filtrate determined by complexometry or by atomic absorption spectrometry, and expressed in the form of Fe₂O3 and Al₂O₃; proceed to titanium extraction⁵¹ also from the filtrate (determined colorimetrically or by atomic absorption), manganese⁵¹ (determined by atomic absorption or ICP-OES) and phosphorus⁵¹ (determined colorimetrically), expressing the results in the form of TiO₂, MnO and P₂O₅; and 2) silica extraction⁵¹ from the residue of sulfuric acid digestion, with 30% NaOH, determined colorimetrically and expressed in the form of SiO₂.

Molecular ratios SiO₂/Al₂O3 (Ki index), SiO₂/Al₂O3 + Fe₂O3 (Kr index) and Al₂O₃/Fe₂O₃⁵² – calculations based on the above determinations.

Dithionite-extractable iron ("free") – extracted with dithionite-citrate-bicarbonate (DCB) and determined by atomic absorption spectrophotometry or ICP-OES. Value expressed in the form of Fe₂O3 or Fe, the latter of which is commonly represented by the symbol Fed.

Water percentage in the saturation paste extract – calculation of the percentage of water saturation contained in a pasty extract produced from a fine earth fraction sample.

Electrical conductivity in the saturation extract – preparation of saturated paste extract by filtration and determination by conductometry.

Soluble salts in the saturation extract – soluble Ca²⁺ and Mg²⁺ are determined by atomic absorption spectroscopy and ICP-OES; K+ and Na+ by flame photometry, both in the diluted saturation extracts; CO₃²⁻ and HCO₃⁻ determined by acidimetry with H₂SO₄; Cl- determined by volumetry with AgNO₃ in the presence of K₂CrO₄; and SO₄²⁻ determined by gravimetry after sulfate precipitation with BaCl₂.

Calcium carbonate equivalent – determined in the fine earth fraction by hot hydrochloric acid attack with 0.5 mol L-1 HCl and acidity titrated with 0.25 mol L-1 NaOH, using 1% phenolphthalein as indicator.

Sulfur – sample attack with hot 1:1 HCl, precipitation with 10% BaCl2 , calcination of BaSO₄ and gravimetric determination of the precipitate.

Mineralogical grain analysis (sand and coarser fractions) – Identification and characterization of mineral constituents, lithofragments, nodules and concretions with a binocular loupe and petrographic microscope. Chemical microtests are used occasionally as complementary technique for the identification of manganese oxides and carbonates or physical tests to investigate whether magnetic minerals are present or not. Occasionally, X-ray diffraction can also be used to confirm the identification of minerals.

Mineralogical analysis of clay and silt fractions – determinations by X-ray diffraction and thermoanalytical techniques.

Tests for characterization of Organossolos⁵³, according to Lynn et al. (1974)

Sample preparation – place a representative sample of organic soil material in a plastic container. If the sample is dry or relatively dry, add water to the container and allow to stand for at least a day. Place the sample on absorbent paper to remove excess moisture. Wrap the paper around the sample and press slowly to ensure a firm contact with the paper. Discard the paper and cut the residue in shape of a cigar, in segments of approximately 1 cm. To determine the fiber content, pyrophosphate solubility or the pH, the pieces of the prepared sample should be "packed" into a 5 cm³ plastic syringe, cut in half lengthwise, so that the half-syringe has a volume of 2.5 cm³. When "packing" the half-syringe, compress the sample sufficiently to saturate the material and force out the trapped air. Do not let water escape. This is the moisture condition to which the residue should return later, when the soil volume is determined by reading on the scale of the syringe.

Fiber determination – place a 2.5 cm3 sample in a 100 mesh sieve and rinse it under a water jet until the effluent becomes clear. Remove excess moisture through the sieve, drying it with absorbent paper. "Repack" the residue into the half-syringe and dry it with absorbent paper until the moisture content reaches the condition described above. Read the volume of the residue on the scale of the cut syringe and record it as % (by volume) of unrubbed fiber. Transfer the residue to a 100 mesh sieve and rub it between thumb and forefinger, under a jet of tap water, until the effluent becomes clear. Dry and "repack" the residue into the half-syringe, as done with the unrubbed fiber. Read the volume on the scale and record it as % (by volume) of rubbed fiber.

Determination of solubility in sodium pyrophosphate – mix the sample contained in the half-syringe (2.5 cm³) with 1 g pyrophosphate crystals and 4 mL of water in a 30 mL container and allow to stand overnight. Remix and insert a piece (0.5 cm x 3 cm) of chromatography paper to absorb the saturated solution. Wait until the paper is completely wet. Remove the final part of the paper, slightly rub the upper part of the strip against another chromatography paper strip to remove excess moisture. Compare the colored paper strip with the color patterns of the Munsell book of color (10YR hue page. The pyrophosphate index (PI) is calculated by subtracting the number obtained for chroma from the value (PI = value - chroma).

pH determination – mix the sample of the half-syringe (2.5 cm³) with 4 mL of 0.015 mol L⁻¹ CaCl2 (at 20:1) and allow to rest for at least 1h to reach equilibrium. Determine the pH by the combined electrode method or with pH paper.

Soil bulk density (Db) – Db = weight of sample dried at 105 °C (24h)/known sample volume.

Organic matter density (Dom) – calculated according to the relationship between Dom = Db - [Db x (% weight MM/100)], where "MM" is "mineral material", based on the premise that the organic material (OMl) has an open structure in which the interstices are occupied by mineral matter (Lynn et al., 1974).

Minimum residue (MR) – It is assumed that, with the complete loss (mineralization) of organic material, the minimum residue represents the mineral composition of the original material (Lynn et al., 1974). The residue represents an estimate of the proportion between the residual and original thickness, and is therefore expressed in cm/cm.

MR = (Dbi - Dom) / Dbr*

where:

Dbi = Bulk density of the initial soil or soil in its original state.

Dbr = Density of residual soil (commonly between 1.2 g cm-3 and 1.7 g cm⁻³).

* Factor 1.5 represents an average density value of the residual soil after subsidence, as proposed by Lynn et al. (1974).

Water content = gravimetric moisture (Wg) – The gravimetric moisture (Wg), expressed in percentage of the soil mass dried at 105 °C (24h), represents the water content at sampling.

Wg = (moist weight - weight after drying at 105 °C) / weight after drying at 105 °C x 100

Mineral content = % mineral material (MM) – determined by muffle furnace combustion.

MM = 100 x (sample weight after drying at 400 °C for 24h* / sample weight after drying at 105 °C for 24h)

* Can be done at 600 °C (6h).

Determination of organic matter (OM)⁵⁴ – performed in previously oven-dried samples (at 105°C for 24h); after muffle furnace combustion (at 600 °C for 6 h), the OM content is determined as the weight difference in comparison with the oven-dried sample.

Von Post decomposition scale (Stanek; Silc, 1977) – this field test consists of squeezing a handful of wet soil with high organic matter content and observing the color of the extracted fluid (which stains the skin and trickles through the fingers of the hand when closed), the nature of the plant fibers, and the residual proportion of the original sample retained in the hand. The 10 sample classes are:

Undecomposed – almost unchanged original plant structure; squeezed in the hand, the sample releases clear water only (no pyrophosphate color).

Slightly decomposed – easily identifiable original plant structure; squeezed in the hand, the sample releases clear-colored (yellowish brown) water.

Very weakly decomposed – identifiable original plant structure; the sample squeezed in the hand releases turbid water and no organic soil material flows through the fingers; the residue left in the palm of one’s hand is not smeary.

Weakly decomposed – hardly identifiable original plant structure; turbid water is released from the sample squeezed in the hand and no organic soil material flows through the fingers; the remaining residue is hardly smeary at all.

Moderately decomposed – barely visible, recognizable but not identifiable original plant structure; the squeezed sample releases turbid brown water and some organic soil material flows through the fingers; the remaining residue is slightly smeary.

Well decomposed – original plant structure is unrecognizable but is more noticeable in the residue left in the hand than in the unsqueezed organic soil material; approximately 1/3 of the organic soil material flows through the fingers, and the remaining residue is very smeary.

Strongly decomposed – almost undistinguishable original plant structure; approximately half of the organic soil material flows through the fingers.

Very strongly decomposed (or extremely decomposed) – undistinguishable original plant structure; approximately 2/3 of the organic soil material flows through the fingers, and the residue, almost completely resistant to decomposition, consists in root filaments and woody material.

Almost completely decomposed – original plant structure nearly unrecognizable; almost all the organic soil material flows through the fingers, as a smeary (spongy) homogeneous mass.

Completely decomposed – unrecognizable original plant structure; all organic soil material flows through the fingers.

The classes (1) to (4) are classified as fibric organic soil material; classes (5) and (6) as hemic organic soil material; and classes (7) to (10) as sapric organic soil material.

(51) Overall quantitative expression of constituents (Si, Al, Fe, Ti, Mn, P) of secondary mineral components of fine earth fraction together with the possible presence of magnetite and ilmenite. Conventionally, they are expressed in the form of SiO₂, Al₂O₃, Fe₂O₃, TiO₂, MnO and P₂O₅.

(52) Indices of the global proportion of constituents (Si, Al, Fe) of the secondary mineral components of the fine earth fraction together with the possible presence of magnetite and ilmenite.

(53) Additional information about methods for soils with high organic matter contents was compiled by Fontana et al. (2017).

(54) The method of total C analysis in an elemental analyzer (CHN) has been used to determine MO in Organossolos. However, there are still no conclusive results.

Appendix E

Symbology of the classes of the 1st, 2nd and 3rd categorical levels

The symbols of the existing soil classes in the SiBCS are listed below to standardize the legends used in soil maps throughout the Country.

The Executive Committee of Soil Classification defined the symbols and proposes their use up to the 3rd level. The 1st and 2nd categorical levels are indicated by capital and the 3rd level by lowercase letters. Thus, the first capital letter represents the 1st level, the second (or second and third, or second, third and fourth) capital letter(s), the 2nd level, and the following, lowercase letter(s), the 3rd categorical level (Table 1). It is worth pointing out that each level is independent and thus each letter at each level has its own significance. It is expected, in this way, to standardize the notation of soil classes for all users of the system. To establish legends of maps or tables, it is suggested to use Arabic numbers sequentially after the alphabetic symbol to identify and separate the soil mapping units.

ARGISSOLOS – P

2nd categorical level

1 ARGISSOLOS BRUNO-ACINZENTADOS – PBAC

2 ARGISSOLOS ACINZENTADOS – PAC

3 ARGISSOLOS AMARELOS – PA

4 ARGISSOLOS VERMELHOS – PV

5 ARGISSOLOS VERMELHO-AMARELOS – PVA

3rd categorical level

1 ARGISSOLOS BRUNO-ACINZENTADOS

1.1 ARGISSOLOS BRUNO-ACINZENTADOS Ta Alumínicos – PBACva

1.2 ARGISSOLOS BRUNO-ACINZENTADOS Alumínicos – PBACa

1.3 ARGISSOLOS BRUNO-ACINZENTADOS Distróficos – PBACd

2 ARGISSOLOS ACINZENTADOS

2.1 ARGISSOLOS ACINZENTADOS Distrocoesos – PACdx

2.2 ARGISSOLOS ACINZENTADOS Distróficos – PACd

2.3 ARGISSOLOS ACINZENTADOS Eutróficos – PACe

3 ARGISSOLOS AMARELOS

3.1 ARGISSOLOS AMARELOS Ta Alumínicos – PAva

3.2 ARGISSOLOS AMARELOS Alumínicos – PAa

3.3 ARGISSOLOS AMARELOS Distrocoesos – PAdx

3.4 ARGISSOLOS AMARELOS Distróficos – PAd

3.5 ARGISSOLOS AMARELOS Eutrocoesos – PAex

3.6 ARGISSOLOS AMARELOS Eutróficos – PAe

4 ARGISSOLOS VERMELHOS

4.1 ARGISSOLOS VERMELHOS Ta Alumínicos – PVva

4.2 ARGISSOLOS VERMELHOS Alumínicos – PVa

4.3 ARGISSOLOS VERMELHOS Ta Distróficos – PVvd

4.4 ARGISSOLOS VERMELHOS Distróficos – PVd

4.5 ARGISSOLOS VERMELHOS Eutroférricos – PVef

4.6 ARGISSOLOS VERMELHOS Eutróficos – PVe

5 ARGISSOLOS VERMELHO-AMARELOS

5.1 ARGISSOLOS VERMELHO-AMARELOS Ta Alumínicos – PVAva

5.2 ARGISSOLOS VERMELHO-AMARELOS Alumínicos – PVAa

5.3 ARGISSOLOS VERMELHO-AMARELOS Ta Distróficos – PVAvd

5.4 ARGISSOLOS VERMELHO-AMARELOS Distróficos – PVAd

5.5 ARGISSOLOS VERMELHO-AMARELOS Eutróficos – PVAe

CAMBISSOLOS – C

2nd categorical level

1 CAMBISSOLOS HÍSTICOS – CI

2 CAMBISSOLOS HÚMICOS – CH

3 CAMBISSOLOS FLÚVICOS – CY

4 CAMBISSOLOS HÁPLICOS – CX

3rd categorical level

1 CAMBISSOLOS HÍSTICOS

1.1 CAMBISSOLOS HÍSTICOS Alumínicos – CIa

1.2 CAMBISSOLOS HÍSTICOS Distróficos – CId

2 CAMBISSOLOS HÚMICOS

2.1 CAMBISSOLOS HÚMICOS Aluminoférricos – CHaf

2.2 CAMBISSOLOS HÚMICOS Alumínicos – CHa

2.3 CAMBISSOLOS HÚMICOS Distroférricos – CHdf

2.4 CAMBISSOLOS HÚMICOS Distróficos – CHd

3 CAMBISSOLOS FLÚVICOS

3.1 CAMBISSOLOS FLÚVICOS Carbonáticos – CYk

3.2 CAMBISSOLOS FLÚVICOS Sódicos – CYn

3.3 CAMBISSOLOS FLÚVICOS Sálicos – CYz

3.4 CAMBISSOLOS FLÚVICOS Alumínicos – CYa

3.5 CAMBISSOLOS FLÚVICOS Ta Distróficos – CYvd

3.6 CAMBISSOLOS FLÚVICOS Ta Eutróficos – CYve

3.7 CAMBISSOLOS FLÚVICOS Tb Distróficos – CYbd

3.8 CAMBISSOLOS FLÚVICOS Tb Eutróficos – CYbe

4 CAMBISSOLOS HÁPLICOS

4.1 CAMBISSOLOS HÁPLICOS Carbonáticos – CXk

4.2 CAMBISSOLOS HÁPLICOS Sódicos – CXn

4.3 CAMBISSOLOS HÁPLICOS Perférricos – CXj

4.4 CAMBISSOLOS HÁPLICOS Ta Alumínicos – CXva

4.5 CAMBISSOLOS HÁPLICOS Ta Distróficos – CXvd

4.6 CAMBISSOLOS HÁPLICOS Ta Eutroférricos – CXvef

4.7 CAMBISSOLOS HÁPLICOS Ta Eutróficos – CXve

4.8 CAMBISSOLOS HÁPLICOS Tb Alumínicos – CXba

4.9 CAMBISSOLOS HÁPLICOS Tb Distroférricos – CXbdf

4.10 CAMBISSOLOS HÁPLICOS Tb Distróficos – CXbd

4.11 CAMBISSOLOS HÁPLICOS Tb Eutroférricos – CXbef

4.12 CAMBISSOLOS HÁPLICOS Tb Eutróficos – CXbe

CHERNOSSOLOS – M

2nd categorical level

1 CHERNOSSOLOS RÊNDZICOS – MD

2 CHERNOSSOLOS EBÂNICOS – ME

3 CHERNOSSOLOS ARGILÚVICOS – MT

4 CHERNOSSOLOS HÁPLICOS – MX

3rd categorical level

1 CHERNOSSOLOS RÊNDZICOS

1.1 CHERNOSSOLOS RÊNDZICOS Petrocálcicos – MDlk

1.2 CHERNOSSOLOS RÊNDZICOS Líticos – MDl

1.3 CHERNOSSOLOS RÊNDZICOS Órticos – MDo

2 CHERNOSSOLOS EBÂNICOS

2.1 CHERNOSSOLOS EBÂNICOS Carbonáticos – MEk

2.2 CHERNOSSOLOS EBÂNICOS Órticos – MEo

3 CHERNOSSOLOS ARGILÚVICOS

3.1 CHERNOSSOLOS ARGILÚVICOS Férricos – MTf

3.2 CHERNOSSOLOS ARGILÚVICOS Carbonáticos – MTk

3.3 CHERNOSSOLOS ARGILÚVICOS Órticos – MTo

4 CHERNOSSOLOS HÁPLICOS

4.1 CHERNOSSOLOS HÁPLICOS Férricos – MXf

4.2 CHERNOSSOLOS HÁPLICOS Carbonáticos – MXk

4.3 CHERNOSSOLOS HÁPLICOS Órticos – MXo

ESPODOSSOLOS – E

2nd categorical level

1 ESPODOSSOLOS HUMILÚVICOS – EK

2 ESPODOSSOLOS FERRILÚVICOS – ES

3 ESPODOSSOLOS FERRI-HUMILÚVICOS – ESK

3rd categorical level

1 ESPODOSSOLOS HUMILÚVICOS

1.1 ESPODOSSOLOS HUMILÚVICOS Hidro-hiperespessos – EKgu

1.2 ESPODOSSOLOS HUMILÚVICOS Hidromórficos – EKg

1.3 ESPODOSSOLOS HUMILÚVICOS Hiperespessos – EKu

1.4 ESPODOSSOLOS HUMILÚVICOS Órticos – EKo

2 ESPODOSSOLOS FERRILÚVICOS

2.1 ESPODOSSOLOS FERRILÚVICOS Hidro-hiperespessos – ESgu

2.2 ESPODOSSOLOS FERRILÚVICOS Hidromórficos – ESg

2.3 ESPODOSSOLOS FERRILÚVICOS Hiperespessos – ESu

2.4 ESPODOSSOLOS FERRILÚVICOS Órticos – ESo

3 ESPODOSSOLOS FERRI-HUMILÚVICOS

3.1 ESPODOSSOLOS FERRI-HUMILÚVICOS Hidro-hiperespessos – ESKgu

3.2 ESPODOSSOLOS FERRI-HUMILÚVICOS Hidromórficos – ESKg

3.3 ESPODOSSOLOS FERRI-HUMILÚVICOS Hiperespessos – ESKu

3.4 ESPODOSSOLOS FERRI-HUMILÚVICOS Órticos – ESKo

GLEISSOLOS – G

2nd categorical level

1 GLEISSOLOS TIOMÓRFICOS – GJ

2 GLEISSOLOS SÁLICOS – GZ

3 GLEISSOLOS MELÂNICOS – GM

4 GLEISSOLOS HÁPLICOS – GX

3rd categorical level

1 GLEISSOLOS TIOMÓRFICOS

1.1 GLEISSOLOS TIOMÓRFICOS Hísticos – GJi

1.2 GLEISSOLOS TIOMÓRFICOS Órticos – GJo

2 GLEISSOLOS SÁLICOS

2.1 GLEISSOLOS SÁLICOS Sódicos – GZn

2.2 GLEISSOLOS SÁLICOS Órticos – GZo

3 GLEISSOLOS MELÂNICOS

3.1 GLEISSOLOS MELÂNICOS Carbonáticos – GMk

3.2 GLEISSOLOS MELÂNICOS Sódicos – GMn

3.3 GLEISSOLOS MELÂNICOS Ta Alumínicos – GMva

3.4 GLEISSOLOS MELÂNICOS Ta Distróficos – GMvd

3.5 GLEISSOLOS MELÂNICOS Ta Eutróficos – GMve

3.6 GLEISSOLOS MELÂNICOS Tb Alumínicos – GMba

3.7 GLEISSOLOS MELÂNICOS Tb Distróficos – GMbd

3.8 GLEISSOLOS MELÂNICOS Tb Eutróficos – GMbe

4 GLEISSOLOS HÁPLICOS

4.1 GLEISSOLOS HÁPLICOS Carbonáticos – GXk

4.2 GLEISSOLOS HÁPLICOS Sódicos – GXn

4.3 GLEISSOLOS HÁPLICOS Ta Alumínicos – GXva

4.4 GLEISSOLOS HÁPLICOS Ta Distróficos – GXvd

4.5 GLEISSOLOS HÁPLICOS Ta Eutróficos – GXve

4.6 GLEISSOLOS HÁPLICOS Tb Alumínicos – GXba

4.7 GLEISSOLOS HÁPLICOS Tb Distróficos – GXbd

4.8 GLEISSOLOS HÁPLICOS Tb Eutróficos – GXbe

LATOSSOLOS – L

2nd categorical level

1 LATOSSOLOS BRUNOS – LB

2 LATOSSOLOS AMARELOS – LA

3 LATOSSOLOS VERMELHOS – LV

4 LATOSSOLOS VERMELHO-AMARELOS – LVA

3rd categorical level

1 LATOSSOLOS BRUNOS

1.1 LATOSSOLOS BRUNOS Aluminoférricos – LBaf

1.2 LATOSSOLOS BRUNOS Alumínicos – LBa

1.3 LATOSSOLOS BRUNOS Distroférricos – LBdf

1.4 LATOSSOLOS BRUNOS Distróficos – LBd

2 LATOSSOLOS AMARELOS

2.1 LATOSSOLOS AMARELOS Acriférricos – LAwf

2.2 LATOSSOLOS AMARELOS Ácricos – LAw

2.3 LATOSSOLOS AMARELOS Alumínicos – LAa

2.4 LATOSSOLOS AMARELOS Distroférricos – LAdf

2.5 LATOSSOLOS AMARELOS Distrocoesos – LAdx

2.6 LATOSSOLOS AMARELOS Distróficos – LAd

2.7 LATOSSOLOS AMARELOS Eutróficos – LAe

3 LATOSSOLOS VERMELHOS

3.1 LATOSSOLOS VERMELHOS Perférricos – LVj

3.2 LATOSSOLOS VERMELHOS Acriférricos – LVwf

3.3 LATOSSOLOS VERMELHOS Ácricos – LVw

3.4 LATOSSOLOS VERMELHOS Aluminoférricos – LVaf

3.5 LATOSSOLOS VERMELHOS Distroférricos – LVdf

3.6 LATOSSOLOS VERMELHOS Distróficos – LVd

3.7 LATOSSOLOS VERMELHOS Eutroférricos – LVef

3.8 LATOSSOLOS VERMELHOS Eutróficos – LVe

4 LATOSSOLOS VERMELHO-AMARELOS

4.1 LATOSSOLOS VERMELHO-AMARELOS Acriférricos – LVAwf

4.2 LATOSSOLOS VERMELHO-AMARELOS Ácricos – LVAw

4.3 LATOSSOLOS VERMELHO-AMARELOS Alumínicos – LVAa

4.4 LATOSSOLOS VERMELHO-AMARELOS Distroférricos – LVAdf

4.5 LATOSSOLOS VERMELHO-AMARELOS Distróficos – LVAd

4.6 LATOSSOLOS VERMELHO-AMARELOS Eutróficos – LVAe

LUVISSOLOS – T

2nd categorical level

1 LUVISSOLOS CRÔMICOS – TC

2 LUVISSOLOS HÁPLICOS – TX

3rd categorical level

1 LUVISSOLOS CRÔMICOS

1.1 LUVISSOLOS CRÔMICOS Carbonáticos – TCk

1.2 LUVISSOLOS CRÔMICOS Pálicos – TCp

1.3 LUVISSOLOS CRÔMICOS Órticos – TCo

2 LUVISSOLOS HÁPLICOS

2.1 LUVISSOLOS HÁPLICOS Pálicos – TXp

2.2 LUVISSOLOS HÁPLICOS Órticos – TXo

NEOSSOLOS – R

2nd categorical level

1 NEOSSOLOS LITÓLICOS – RL

2 NEOSSOLOS FLÚVICOS – RY

3 NEOSSOLOS REGOLÍTICOS – RR

4 NEOSSOLOS QUARTZARÊNICOS – RQ

3rd categorical level

1 NEOSSOLOS LITÓLICOS

1.1 NEOSSOLOS LITÓLICOS Hísticos – RLi

1.2 NEOSSOLOS LITÓLICOS Húmicos – RLh

1.3 NEOSSOLOS LITÓLICOS Carbonáticos – RLk

1.4 NEOSSOLOS LITÓLICOS Chernossólicos – RLm

1.5 NEOSSOLOS LITÓLICOS Distróficos – RLd

1.6 NEOSSOLOS LITÓLICOS Eutróficos – RLe

2 NEOSSOLOS FLÚVICOS

2.1 NEOSSOLOS FLÚVICOS Carbonáticos – RYk

2.2 NEOSSOLOS FLÚVICOS Sódicos – RYn

2.3 NEOSSOLOS FLÚVICOS Sálicos – RYz

2.4 NEOSSOLOS FLÚVICOS Psamíticos – RYq

2.5 NEOSSOLOS FLÚVICOS Ta Eutróficos – RYve

2.6 NEOSSOLOS FLÚVICOS Tb Distróficos – RYbd

2.7 NEOSSOLOS FLÚVICOS Tb Eutróficos – RYbe

3 NEOSSOLOS REGOLÍTICOS

3.1 NEOSSOLOS REGOLÍTICOS Psamíticos – RRq

3.2 NEOSSOLOS REGOLÍTICOS Húmicos – RRh

3.3 NEOSSOLOS REGOLÍTICOS Distróficos – RRd

3.4 NEOSSOLOS REGOLÍTICOS Eutróficos – RRe

4 NEOSSOLOS QUARTZARÊNICOS

4.1 NEOSSOLOS QUARTZARÊNICOS Hidromórficos – RQg

4.2 NEOSSOLOS QUARTZARÊNICOS Órticos – RQo

NITOSSOLOS – N

2nd categorical level

1 NITOSSOLOS BRUNOS – NB

2 NITOSSOLOS VERMELHOS – NV

3 NITOSSOLOS HÁPLICOS – NX

3rd categorical level

1 NITOSSOLOS BRUNOS

1.1 NITOSSOLOS BRUNOS Aluminoférricos – NBaf

1.2 NITOSSOLOS BRUNOS Alumínicos – NBa

1.3 NITOSSOLOS BRUNOS Distroférricos – NBdf

1.4 NITOSSOLOS BRUNOS Distróficos – NBd

2 NITOSSOLOS VERMELHOS

2.1 NITOSSOLOS VERMELHOS Ta Alumínicos– NVva

2.2 NITOSSOLOS VERMELHOS Alumínicos – NVa

2.3 NITOSSOLOS VERMELHOS Distroférricos – NVdf

2.4 NITOSSOLOS VERMELHOS Distróficos – NVd

2.5 NITOSSOLOS VERMELHOS Eutroférricos – NVef

2.6 NITOSSOLOS VERMELHOS Eutróficos – NVe

3 NITOSSOLOS HÁPLICOS

3.1 NITOSSOLOS HÁPLICOS Ta Alumínicos – NXva

3.2 NITOSSOLOS HÁPLICOS Alumínicos – NXa

3.3 NITOSSOLOS HÁPLICOS Distróficos – NXd

3.4 NITOSSOLOS HÁPLICOS Eutróficos – NXe

ORGANOSSOLOS – O

2nd categorical level

1 ORGANOSSOLOS TIOMÓRFICOS – OJ

2 ORGANOSSOLOS FÓLICOS – OO

3 ORGANOSSOLOS HÁPLICOS – OX

3rd categorical level

1 ORGANOSSOLOS TIOMÓRFICOS

1.1 ORGANOSSOLOS TIOMÓRFICOS Fíbricos – OJfi

1.2 ORGANOSSOLOS TIOMÓRFICOS Hêmicos – OJy

1.3 ORGANOSSOLOS TIOMÓRFICOS Sápricos – OJs

2 ORGANOSSOLOS FÓLICOS

2.1 ORGANOSSOLOS FÓLICOS Fíbricos – OOfi

2.2 ORGANOSSOLOS FÓLICOS Hêmicos – OOy

2.3 ORGANOSSOLOS FÓLICOS Sápricos – OOs

3 ORGANOSSOLOS HÁPLICOS

3.1 ORGANOSSOLOS HÁPLICOS Fíbricos – OXfi

3.2 ORGANOSSOLOS HÁPLICOS Hêmicos – OXy

3.3 ORGANOSSOLOS HÁPLICOS Sápricos – OXs

PLANOSSOLOS – S

2nd categorical level

1 PLANOSSOLOS NÁTRICOS – SN

2 PLANOSSOLOS HÁPLICOS – SX

3rd categorical level

1 PLANOSSOLOS NÁTRICOS

1.1 PLANOSSOLOS NÁTRICOS Carbonáticos – SNk

1.2 PLANOSSOLOS NÁTRICOS Sálicos – SNz

1.3 PLANOSSOLOS NÁTRICOS Órticos – SNo

2 PLANOSSOLOS HÁPLICOS

2.1 PLANOSSOLOS HÁPLICOS Carbonáticos – SXk

2.2 PLANOSSOLOS HÁPLICOS Sálicos – SXz

2.3 PLANOSSOLOS HÁPLICOS Alumínicos – SXa

2.4 PLANOSSOLOS HÁPLICOS Distróficos – SXd

2.5 PLANOSSOLOS HÁPLICOS Eutróficos – SXe

PLINTOSSOLOS – F

2nd categorical level

1 PLINTOSSOLOS PÉTRICOS – FF

2 PLINTOSSOLOS ARGILÚVICOS – FT

3 PLINTOSSOLOS HÁPLICOS – FX

3rd categorical level

1 PLINTOSSOLOS PÉTRICOS

1.1 PLINTOSSOLOS PÉTRICOS Litoplínticos – FFlf

1.2 PLINTOSSOLOS PÉTRICOS Concrecionários – FFc

2 PLINTOSSOLOS ARGILÚVICOS

2.1 PLINTOSSOLOS ARGILÚVICOS Alumínicos – FTa

2.2 PLINTOSSOLOS ARGILÚVICOS Distróficos – FTd

2.3 PLINTOSSOLOS ARGILÚVICOS Eutróficos – FTe

3 PLINTOSSOLOS HÁPLICOS

3.1 PLINTOSSOLOS HÁPLICOS Ácricos – FXw

3.2 PLINTOSSOLOS HÁPLICOS Alumínicos – FXa

3.3 PLINTOSSOLOS HÁPLICOS Distróficos – FXd

3.4 PLINTOSSOLOS HÁPLICOS Eutróficos – FXe

VERTISSOLOS – V

2nd categorical level

1 VERTISSOLOS HIDROMÓRFICOS – VG

2 VERTISSOLOS EBÂNICOS – VE

3 VERTISSOLOS HÁPLICOS – VX

3rd categorical level

1 VERTISSOLOS HIDROMÓRFICOS

1.1 VERTISSOLOS HIDROMÓRFICOS Carbonáticos – VGk

1.2 VERTISSOLOS HIDROMÓRFICOS Sódicos – VGn

1.3 VERTISSOLOS HIDROMÓRFICOS Sálicos – VGz

1.4 VERTISSOLOS HIDROMÓRFICOS Órticos – VGo

2 VERTISSOLOS EBÂNICOS

2.1 VERTISSOLOS EBÂNICOS Carbonáticos – VEk

2.2 VERTISSOLOS EBÂNICOS Sódicos – VEn

2.3 VERTISSOLOS EBÂNICOS Órticos – VEo

3 VERTISSOLOS HÁPLICOS

3.1 VERTISSOLOS HÁPLICOS Carbonáticos – VXk

3.2 VERTISSOLOS HÁPLICOS Sódicos – VXn

3.3 VERTISSOLOS HÁPLICOS Sálicos – VXz

3.4 VERTISSOLOS HÁPLICOS Órticos – VXo

(To see the table as an image, click here).

Table 1. Symbols of the soil classes of the 1st, 2nd and 3rd categorical levels.

1st Level

2nd Level

3rd Level

C – CAMBISSOLO

A – AMARELO

a – Alumínico

E – ESPODOSSOLO

AC – ACINZENTADO

af – Aluminoférrico

F – PLINTOSSOLO

B – BRUNO

b – Argila de atividade baixa

G – GLEISSOLO

BAC – BRUNO-ACINZENTADO

c – Concrecionário

L – LATOSSOLO

C – CRÔMICO

d – Distrófico

M – CHERNOSSOLO

D – RÊNDZICO

df – Distroférrico

N – NITOSSOLO

E – EBÂNICO

dx – Distrocoeso

O – ORGANOSSOLO

F – PÉTRICO

e – Eutrófico

P – ARGISSOLO

G – HIDROMÓRFICO

ef – Eutroférrico

R – NEOSSOLO

H – HÚMICO

ex – Eutrocoeso

S – PLANOSSOLO

I – HÍSTICO

f – Férrico

T – LUVISSOLO

J – TIOMÓRFICO

fi – Fíbrico

V – VERTISSOLO

K – HUMILÚVICO

g – Hidromórfico

L – LITÓLICO

h – Húmico

M – MELÂNICO

i – Hístico

N – NÁTRICO

j – Perférrico

O – FÓLICO

k – Carbonático

Q – QUARTZARÊNICO

l – Lítico

R – REGOLÍTICO

lf – Litoplíntico

S – FERRILÚVICO

lk – Petrocálcico

SK – FERRI-HUMILÚVICO

m – Chernossólico

T – ARGILÚVICO

n – Sódico

V – VERMELHO

o – Órtico

VA – VERMELHO-AMARELO

p – Pálico

X – HÁPLICO

q – Psamítico

Y – FLÚVICO

r – Saprolítico

Z – SÁLICO

s – Sáprico

t – Argilúvico

u – Hiperespesso

v – Argila de atividade alta

w – Ácrico

wf – Acriférrico

x – Coeso

y – Hêmico

z – Sálico

Appendix F

Terrain types

Terrain types are not soil classes. In surveys, they should be detailed as components of mapping units or as special mapping units. They include borrow pits and waste dumps, landfills, garbage dumps, mining areas, gravel deposits, mobile dunes, beaches, rugged cliffs and rocky outcrops, marked on soil maps and represented by appropriate cartographic conventions. Some examples of terrain types are described below.

Rock outcrops – Consist of the outcropping of different types of rocks, soft or hard, which are bare or covered with minor proportions of detrital material not classifiable as soil.

Dunes – Comprise formations or accumulations formed by the mechanical action of winds, commonly sandy, and constitute undulations of different sizes on the terrain. They can be mobile or fixed (when stabilized). They are not considered as soil if the pedogenetic horizons are not developed, not even the A horizon.

Gravel deposits – Refers to areas where more than 90% of the total volume of the soil mass is composed of mineral material with a diameter > 2 cm, occurring from the surface.

Examples of symbols for all terrain types.

AR – Rock outcrops

AE – Borrow pits

At – Landfills

Ca – Gravel deposits

Dn – Dunes

Lx – Dumps

Mi – Mining areas

Pr – Beaches

Sa – Salt mines

Sb –Shell middens

Appendix G

Ordering of legends of soil identification

The proposed organization of legends of soil maps is shown in Table 1.

(To see the table as an image, click here).

Table 1. Criteria for the organization of soil legends.

1st Criterion

2nd Criterion

3rd Criterion

Relate the mapping units (MU) as indicated in Appendix E, up to the 3rd categorical level, based on the 1st component

Notes:

a) The MU with the lowest number of components should appear in the 1st place.

b) The first criterion applies to all other components.

a) Order the classes of the 4th categorical level alphabetically.

Examples:

"abrúptico"

"latossólico"

"léptico"

"planossólico"

"tiônico"

"típico" etc.

b) Order from the simplest classes (with only one qualifier at the fourth level) to those with the most qualifiers.

4th Criterion

5th Criterion

a) Activity of the clay fraction "Ta" before "Tb".

b) Textural grouping: "very fine clayey," "clayey", "silty", "loamy ", and lastly "sandy".

c) Type of surface horizon: "histic", "humic A", "chernozemic A", "prominent A ", "anthropic A", "moderate A" and lastly "weak A".

d) Phases of:

1) Erosion (soils with eroded phase after those without this phase).

2) Stoniness (soils with stony phase after those without this phase).

3) Rockiness (soils with rocky phase after those without this phase).

4) Vegetation (order as indicated in Chapter 19).

5) Relief (order as indicated in Chapter 19, Relief phases).

6) Substrate (soil with a substrate phase after those without this phase).

a) If there are undifferentiated groups and/or soil complexes, both will be placed after the simple MU and/or associations, however, according to the previous criteria.

b) List the types of terrain in the order indicated in Appendix F and at the end of the legend (after the simple MU and/or associations and/ or undifferentiated groups and/ or soil complexes).

The notation of the soil classes should be as defined in Chapter 3 (Nomenclature of the classes).

Appendix H

Standardization of the colors of the classes of the 1st and 2nd categorical levels for use in soil maps

Color convention for soil maps (Systems: RGB, CMYK and HSV).

Argissolos

1st categorical level

Argissolos – P
R=255 G=167 B=127
C=0 M=35 Y=50 K=0
H=18 S=50 V=100

2nd categorical level

Argissolos Bruno-Acinzentados – PBAC
R=255 G=200 B=250
C=3 M=24 Y=0 K=0
H=305 S=22 V=100

Argissolos Acinzentados – PAC
R=253 G=241 B=240
C=1 M=5 Y=6 K=0
H=10 S=5 V=99

Argissolos Amarelos – PA
R=241 G=204 B=200
C=5 M=20 Y=22 K=0
H=7 S=18 V=95

Argissolos Vermelhos – PV
R=240 G=127 B=127
C=1 M=63 Y=40 K=0
H=0 S=47 V=94

Argissolos Vermelho-Amarelos – PVA
R=255 G=167 B=127
C=0 M=35 Y=50 K=0
H=18 S=50 V=100

Cambissolos

1st categorical level

Cambissolos – C
R=215 G=197 B=165
C=16 M=19 Y=37 K=0
H=38 S=23 V=84

2nd categorical level

Cambissolos Hísticos – CI
R=170 G=134 B=105
C=32 M=45 Y=61 K=6
H=27 S=38 V=67

Cambissolos Húmicos – CH
R=207 G=182 B=128
C=20 M=25 Y=57 K=0
H=41 S=38 V=81

Cambissolos Flúvicos – CY
R=235 G=219 B=191
C=7 M=11 Y=25 K=0
H=38 S=19 V=92

Cambissolos Háplicos – CX
R=215 G=197 B=165
C=16 M=19 Y=37 K=0
H=38 S=23 V=84

Chernossolos

1st categorical level

Chernossolos – M
R=170 G=134 B=134
C=34 M=48 Y=40 K=3
H=0 S=21 V=67

2nd categorical level

Chernossolos Rêndzicos – MD
R=142 G=104 B=86
C=38 M=57 Y=64 K=18
H=19 S=39 V=56

Chernossolos Ebânicos – ME
R=170 G=134 B=134
C=34 M=48 y=40 K=3
H=0 S=21 V=67

Chernossolos Argilúvicos – MT
R=156 G=74 B=78
C=30 M=59 Y=62 K=17
H=357 S=53 V=61

Chernossolos Háplicos – MX
R=156 G=95 B=95
C=34 M=67 Y=54 K=14
H=0 S=39 V=61

Espodossolos

1st categorical level

Espodossolos – E
R=206 G=190 B=198
C=18 M=24 Y=14 K=0
H=330 S=8 V=81

2nd categorical level

Espodossolos Humilúvicos – EK
R=193 G=190 B=197
C=24 M=21 Y=16 K=0
H=266 S=4 V=77

Espodossolos Ferrilúvicos – ES
R=206 G=190 B=198
C=18 M=24 Y=14 K=0
H=330 S=8 V=81

Espodossolos Ferri-humilúvicos – ESK
R=182 G=190 B=197
C=29 M=19 Y=17 K=0
H=208 S=8 V=77

Gleissolos

1st categorical level

Gleissolos – G
R=182 G=216 B=238
C=27 M=5 Y=2 K=0
H=204 S=24 V=93

2nd categorical level

Gleissolos Tiomórficos – GJ
R=108 G=163 B=205
C=58 M=25 Y=6 K=0
H=206 S=47 V=80

Gleissolos Sálicos – GZ
R=94 G=180 B=230
C=57 M=13 Y=0 K=0
H=202 S=59 V=90

Gleissolos Melânicos – GM
R=120 G=252 B=250
C=40 M=0 Y=11 K=0
H=179 S=52 V=99

Gleissolos Háplicos – GX
R=182 G=216 B=238
C=27 M=5 Y=2 K=0
H=204 S=24 V=93

Latossolos

1st categorical level

Latossolos – L
R=254 G=204 B=92
C=1 M=20 Y=74 K=0
H=41 S=64 V=99

2nd categorical level

Latossolos Brunos – LB
R=168 G=112 B=0
C=29 M=55 Y=100 K=13
H=40 S=100 V=66

Latossolos Amarelos – LA
R=254 G=204 B=92
C=1 M=20 Y=74 K=0
H=41 S=64 V=99

Latossolos Vermelhos – LV
R=244 G=185 B=128
C=3 M=30 Y=54 K=0
H=29 S=48 V=96

Latossolos Vermelho-Amarelos – LVA
R=247 G=209 B=166
C=2 M=19 Y=36 K=0
H=32 S=33 V=97

Luvissolos

1st categorical level

Luvissolos – T
R=212 G=150 B=22
C=17 M=42 Y=100 K=1
H=40 S=90 V=83

2nd categorical level

Luvissolos Crômicos – TC
R=212 G=150 B=22
C=17 M=42 Y=100 K=1
H=40 S=90 V=83

Luvissolos Háplicos – TX
R=212 G=179 B=0
C=19 M=25 Y=100 K=0
H=51 S=100 V=83

Neossolos

1st categorical level

Neossolos – R
R=255 G=254 B=115
C=4 M=0 Y=66 K=0
H=60 S=55 V=100

2nd categorical level

Neossolos Litólicos – RL
R=150 G=149 B=149
C=44 M=36 Y=37 K=2
H=0 S=1 V=59

Neossolos Flúvicos – RY
R=238 G=235 B=220
C=6 M=5 Y=13 K=0
H=50 S=8 V=93

Neossolos Regolíticos – RR
R=207 G=206 B=206
C=18 M=14 Y=14 K=0
H=0 S=1 V=81

Neossolos Quartzarênicoss – RQ
R=255 G=254 B=115
C=4 M=0 Y=66 K=0
H=60 S=55 V=100

Nitossolos

1st categorical level

Nitossolos – N
R=168 G=56 B=0
C=23 M=88 Y=100 K=18
H=20 S=100 V=66

2nd categorical level

Nitossolos Brunos – NB
R=104 G=53 B=10
C=38 M=75 Y=100 K=47
H=27 S=90 V=41

Nitossolos Vermelhos – NV
R=168 G=56 B=0
C=23 M=88 Y=100 K=18
H=20 S=100 V=66

Nitossolos Háplicos – NX
R=115 G=76 B=0
C=41 M=62 Y=100 K=36
H=40 S=100 V=45

Organossolos

1st categorical level

Organossolos – O
R=101 G=78 B=156
C=72 M=81 Y=2 K=0
H=258 S=50 V=61

2nd categorical level

Organossolos Tiomórficos – OJ
R=66 G=48 B=150
C=91 M=97 Y=0 K=0
H=261 S=68 V=59

Organossolos Fólicos – OO
R=101 G=78 B=156
C=72 M=81 Y=2 K=0
H=258 S=50 V=61

Organossolos Háplicos – OX
R=167 G=179 B=213
C=34 M=24 Y=3 K=0
H=224 S=22 V=84

Planossolos

1st categorical level

Planossolos – S
R=181 G=214 B=174
C=30 M=2 Y=39 K=0
H=109 S=19 V=84

2nd categorical level

Planossolos Nátricos – SN
R=137 G=202 B=199
C=46 M=3 Y=24 K=0
H=177 S=32 V=79

Planossolos Háplicos – SX
R=181 G=214 B=174
C=30 M=2 Y=39 K=0
H=109 S=19 V=84

Plintossolos

1st categorical level

Plintossolos – F
R=214 G=186 B=201
C=15 M=27 Y=10 K=0
H=328 S=13 V=84

2nd categorical level

Plintossolos Pétricos – FF
R=236 G=172 B=203
C=4 M=39 Y=1 K=0
H=331 S=27 V=93

Plintossolos Argilúvicos – FT
R=236 G=135 B=203
C=8 M=56 Y=0 K=0
H=320 S=43 V=93

Plintossolos Háplicos – FX
R=214 G=186 B=201
C=15 M=27 Y=10 K=0
H=328 S=13 V=84

Vertissolos

1st categorical level

Vertissolos – V
R=158 G=170 B=133
C=41 M=24 Y=54 K=1
H=79 S=22 V=67

2nd categorical level

Vertissolos Hidromórficos – VG
R=158 G=170 B=133
C=41 M=24 Y=54 K=1
H=79 S=22 V=67

Vertissolos Ebânicos – VE
R=134 G=143 B=114
C=49 M=33 Y=59 K=7
H=79 S=20 V=56

Vertissolos Háplicos – VX
R=192 G=192 B=145
C=27 M=17 Y=49 K=0
H=60 S=24 V=75

Appendix I

Agreement between the classes of the SiBCS and of previous classifications

(To see the table as an image, click here).

SiBCS (2018)

Previous classifications used by Embrapa Solos

ARGISSOLOS

Rubrozéns, Podzólicos Bruno-Acinzentados Distróficos or Álicos, Podzólicos Vermelho-Amarelos Distróficos or Álicos Ta, Podzólicos Vermelho-Amarelos Tb, a small part of Terra Roxa Estruturada, of Terra Roxa Estruturada Similar, of Terra Bruna Estruturada and of Terra Bruna Estruturada Similar fulfilling the condition of the textural gradient for textural B, in any case Eutróficas, Distróficas or Álicas and more recently, Podzólicos Vermelho-Escuros Tb and Podzólicos Amarelos.

CAMBISSOLOS

Cambissolos Eutróficos, Distróficos and Álicos Ta and Tb, except for Cambissolos Eutróficos with a chernozemic A horizon and high activity clay.

CHERNOSSOLOS

Rendzinas, Brunizéns, Brunizéns Avermelhados and Brunizéns Hidromórficos.

ESPODOSSOLOS

Podzol, including Podzol Hidromórfico.

GLEISSOLOS

Glei Pouco Húmicos, Glei Húmicos, part of the Hidromórficos Cinzentos (without abrupt textural change), Glei Tiomórficos and Solonchaks with a gley horizon.

LATOSSOLOS

Latossolos, excepting some previously identified modalities such as Latossolos Plínticos.

LUVISSOLOS

Brunos Não Cálcicos, Podzólicos Vermelho-Amarelos Eutróficos Ta, Podzólicos Bruno-Acinzentados Eutróficos and Podzólicos Vermelho-Escuros Eutróficos Ta.

NEOSSOLOS

Litossolos, Solos Litólicos, Regossolos, Solos Aluviais and Areias Quartzosas (Distróficas, Marinhas and Hidromórficas).

NITOSSOLOS

Terra Roxa Estruturada, Terra Roxa Estruturada Similar, Terra Bruna Estruturada, Terra Bruna Estruturada Similar, some Podzólicos Vermelho-Escuros Tb and some Podzólicos Vermelho-Amarelos Tb.

ORGANOSSOLOS

Solos Orgânicos, Solos Semiorgânicos, Solos Tiomórficos Turfosos and part of the Solos Litólicos Turfosos with a histic horizon (thickness ≥ 30 cm).

PLANOSSOLOS

Planossolos, Solonetz Solodizados and Hidromórficos Cinzentos with abrupt textural change.

PLINTOSSOLOS

Lateritas Hidromórficas, part of the Podzólicos Plínticos, part of the Glei Húmicos and of the Glei Pouco Húmicos Plínticos and some of the possible Latossolos Plínticos.

VERTISSOLOS

Vertissolos, including the hidromórficos.

Appendix J

Approximate agreement between soil classes of high categorical levels in the SiBCS, WRB and Soil Taxonomy

(To see the table as an image, click here).

SiBCS (2018)

WRB (IUSS Working Group WRB, 2015⁵⁵)

Soil Taxonomy (United States, 1999⁵⁶, 2014⁵⁷)

Argissolos

Acrisols; Lixisols; Alisols

Ultisols; some Oxisols (Kandic)

Cambissolos

Cambisols

Inceptisols

Chernossolos

Phaeozems; Kastanozems; Chernozems (some)

Molisols (only Ta)

Espodossolos

Podzols

Spodosols

Gleissolos

Gleysols; Stagnosols (some)

Entisols (Aqu-alf-and-ent-ept-)

(Gleissolos Sálicos)

Solonchaks

Aridisols, Entisols (Aqu-sulfa-hydra-salic)

Latossolos

Ferralsols

Oxisols

Luvissolos

Luvisols

Alfisols, Aridisols (Argids)

Neossolos

-------

Entisols

(Neossolos Flúvicos)

Fluvisols

(Fluvents)

(Neossolos Litólicos)

Leptosols

(Lithic....Orthents); (Lithic...Psamments)

(Neossolos Quartzarênicos)

Arenosols

(Quartzipsamments)

(Neossolos Regolíticos)

Regosols

(Psamments)

Nitossolos

Nitisols; Lixisols or Alisols

Ultisols, Oxisols (Kandic), Alfisols

Organossolos

Histosols

Histosols

Planossolos

Planosols

Alfisols

(Planossolos Nátricos)

Solonetz

Natr (ust-ud) alf

(Planossolos Háplicos)

Planosols

Albaquults, Albaqualfs, Plinthaqu(alf-ept-ox-ult)

Plintossolos

Plinthosols

Plinthic subgroups (several classes of Oxisols, Ultisols, Alfisols, Entisols, Inceptisols)

Vertissolos

Vertisols

Vertisols

Not classified
in Brazil

Cryosols

Gelisols

Anthrosols; Technosols

---------

Andosols

Andisols

Umbrisols

Some Umbric subgroups

Gypsisols

Great Group of Aridisols (Gypsi-)

Durisols

Several Great Groups Dur- of Alfisols, Andisols, Aridisols, Inceptisols, Molisol, etc.

Calcisols

Several Great Groups of Alfisols, Aridisols, Inceptisols, Molisols, Vertisols, etc.

Albeluvisols

Some Alb_ Gloss_ classes

(55) World Reference Base for Soil Resources (WRB), universal system recognized by the International Union of Soil Science (IUSS) and FAO. More information about WRB is available at: <http://www.fao.org/3/a-i3794e.pdf>.

(56) Available at: <https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_051232.pdf>.

(57) Available at: <https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/class/taxonomy/?cid=nrcs142p2_053580>.

Appendix K

Representative profiles of soil classes

Figure 1. Profile of Argissolo Bruno-Acinzentado (Alfredo Wagner, SC, Brazil).

Photo by: Humberto Gonçalves dos Santos

Figure 2. Profile of Argissolo Acinzentado (Pacajus, CE, Brazil).

Photo by: José Francisco Lumbreras

Figure 3. Profile of Argissolo Amarelo (Teixeira de Freitas, BA, Brazil).

Photo by: José Coelho de Araújo Filho

Figure 4. Profile of Argissolo Vermelho (Tarauacá, AC, Brazil).

Photo by: Sergio Hideiti Shimizu

Figure 5. Profile of Argissolo Vermelho-Amarelo (Cambuci, RJ, Brazil).

Photo by: José Francisco Lumbreras

Figure 6. Profile of Cambissolo Hístico (Bom Jardim da Serra, SC, Brazil).

Photo by: Jaime Antonio de Almeida

Figure 7. Profile of Cambissolo Húmico (Água Doce, SC, Brazil).

Photo by: Humberto Gonçalves dos Santos

Figure 8. Profile of Cambissolo Flúvico (Ipojuca, PE, Brazil).

Photo by: Flávio Adriano Marques

Figure 9. Profile of Cambissolo Háplico (Arraial do Cabo, RJ, Brazil).

Photo by: José Francisco Lumbreras

Figure 10. Profile of Chernossolo Rêndzico (Apodi, RN, Brazil).

Photo by: Sergio Hideiti Shimizu

Figure 11. Profile of Chernossolo Ebânico (Aceguá, RS, Brazil).

Photo by: José Francisco Lumbreras

Figure 12. Profile of Chernossolo Argilúvico (Nazaré da Mata, PE, Brazil).

Photo by: José Coelho de Araújo Filho

Figure 13. Profile of Chernossolo Háplico (Corumbá, MS, Brazil).

Photo by: Sergio Hideiti Shimizu

Figure 14. Profile of Espodossolo Humilúvico (Cananeia, SP, Brazil).

Photo by: Maurício Rizzato Coelho

Figure 15. Profile of Espodossolo Ferrilúvico (Ilha Comprida, SP, Brazil).

Photo by: Maurício Rizzato Coelho

Figure 16. Profile of Espodossolo Ferri-Humilúvico (Bertioga, SP, Brazil).

Photo by: Maurício Rizzato Coelho

Figure 17. Profile of Gleissolo Tiomórfico (Cabo Frio, RJ, Brazil).

Photo by: Paulo Klinger Tito Jacomine

Figure 18. Profile of Gleissolo Sálico (Quissamã, RJ, Brazil).

Photo by: Amaury de Carvalho Filho

Figure 19. Profile of Gleissolo Melânico (Boa Esperança, MG, Brazil).

Photo by: Paulo Klinger Tito Jacomine

Figure 20. Profile of Gleissolo Háplico (Bonfim, RR, Brazil).

Photo by:Sergio Hideiti Shimizu

Figure 21. Profile of Latossolo Bruno (Vacaria, RS, Brazil).

Photo by: José Francisco Lumbreras

Figure 22. Profile of Latossolo Amarelo (Araripina, PE, Brazil).

Photo by: José Coelho de Araújo Filho

Figure 23. Corte de estrada em área de Latossolo Bruno (Vacaria, RS, Brazil).

Photo by: José Francisco Lumbreras

Figure 24. Profile of Latossolo Vermelho (Lagoa Formosa, MG, Brazil).

Photo by: Humberto Gonçalves dos Santos

Figure 25. Profile of Latossolo Vermelho-Amarelo (Rio Paranaíba, MG, Brazil).

Photo by: Maria de Lourdes Mendonça Santos Brefin

Figure 26. Profile of Luvissolo Crômico (Cabrobó, PE, Brazil).

Photo by: José Francisco Lumbreras

Figure 27. Profile of Luvissolo Háplico (Santa Maria, RS, Brazil).

Photo by: Sergio Hideiti Shimizu

Figure 28. Profile of Neossolo Litólico (Caracol, MS, Brazil).

Photo by: Waldir de Carvalho Júnior

Figure 29. Profile of Neossolo Flúvico (São Cristóvão, SE, Brazil).

Photo by: Paulo Klinger Tito Jacomine

Figure 30. Profile of Neossolo Regolítico (Salgueiro, PE, Brazil).

Photo by: José Francisco Lumbreras

Figure 31. Profile of Neossolo Quartzarênico (Corumbá, MS, Brazil).

Photo by: Sergio Hideiti Shimizu

Figure 32. Profile of Nitossolo Bruno (Painel, SC, Brazil).

Photo by: Humberto Gonçalves dos Santos

Figure 33. Profile of Nitossolo Vermelho (Bodoquena, MS, Brazil).

Photo by: José Francisco Lumbreras

Figure 34. Profile of Nitossolo Háplico (São Carlos, SP, Brazil).

Photo by: Humberto Gonçalves dos Santos

Figure 35. Profile of Organossolo Tiomórfico (Coruripe, AL, Brazil).

Photo by: Paulo Klinger Tito Jacomine

Figure 36. Profile of Organossolo Fólico (Bom Jardim da Serra, SC, Brazil).

Photo by: Sergio Hideiti Shimizu

Figure 37. Profile of Organossolo Háplico (Indianápolis, MG, Brazil).

Photo by: Sergio Hideiti Shimizu

Figure 38. Profile of Planossolo Nátrico (Quixadá, CE, Brazil).

Photo by: Sergio Hideiti Shimizu

Figure 39. Profile of Planossolo Háplico (Pelotas, RS, Brazil).

Photo by: Sergio Hideiti Shimizu

Figure 40. Profile of Plintossolo Pétrico (Monte do Carmo, TO, Brazil).

Photo by: José Francisco Lumbreras

Figure 41. Profile of Plintossolo Argilúvico (Goiana, PE, Brazil).

Photo by: Manoel Batista de Oliveira Neto

Figure 42. Profile of Plintossolo Háplico (Porto Velho, RO, Brazil).

Photo by: Sergio Hideiti Shimizu

Figure 43. Profile of Vertissolo Hidromórfico (Parnamirim, PE, Brazil).

Photo by: José Coelho de Araújo FIlho

Figure 44. Profile of Vertissolo Ebânico (Porto Franco, MA, Brazil).

Photo by: Paulo Klinger Tito Jacomine

Figure 45. Profile of Vertissolo Háplico (Terra Nova, BA, Brazil).

Photo by: Marcelo Metri Correa

Tables

Chapter 2

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Chapter 3

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Appendix A

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Appendix C

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Appendix E

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Appendix G

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Appendix I

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Appendix J

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