Brazilian Agricultural Research Corporation – Embrapa

Embrapa Soils

Ministry of Agriculture, Livestock and Food Supply

DOCUMENTOS 205

SPS 2018
6th Sustainable Phosphorus Summit

Book of abstracts

Vinicius de Melo Benites

Technical Editor

Embrapa Soils
Rio de Janeiro, RJ
2019

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

Editorial Supervision: Jacqueline Silva Rezende Mattos

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1st edition

E-book (2019)

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Reproduction of this publication, in its entirety or in part, is not permitted, it is a breach of copyright (Act no. 9.610).

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Embrapa

Sustainable Phosphorus Summit (6.: 2018 : Brasília, DF)

Book of abstracts / Vinicius de Melo Benites, technical editor. – Rio de Janeiro : Embrapa Solos, 2019.

E-book. – (Documentos / Embrapa Solos, ISSN 1517-2627 ; 205).

1. Phosphorus. 2. Fertilizers. 3. Agriculture. I. Benites, Vinicius de Melo. II. Embrapa Solos. III. Título.

CDD 631.85

Luciana Sampaio de Araujo (CRB7-5165)

© Embrapa, 2019

Author

Vinicius de Melo Benites

Engenheiro-agrônomo, doutor em Agronomia, pesquisador da Embrapa Solos, Rio de Janeiro, RJ

Presentation

On behalf of the international scientific committee and local organizing committee it is a pleasure for me to announce that the 6th Sustainable Phosphorus Summit (SPS 2018) will be held in Brasilia, Brazil, from 20th to 22nd August, 2018.

SPS 2018 is the sixth of a young and successful series of Sustainable Phosphorus Summits that was launched in Linköping (Sweden) in 2010, and then went to Tempe (USA) in 2011; Sydney (Australia) in 2012; Montpellier (France) in 2014 and Kunming (China) in 2016.

The dynamic and interdisciplinary format of the Summit seeks to bring together diverse science, policy and industry stakeholders from different parts of the food production and consumption chain, to advance knowledge and identify actions regarding the role of phosphorus availability and accessibility in food security and agriculture, protecting the environment, and supporting rural and urban livelihoods.

SPS 2018 will bring together scientists and stakeholders from across the globe, including developing and emerging countries, to foster exchange of views across disciplinary boundaries and societal domains. In order to better improve phosphorus use efficiency along the whole food chain, growing public awareness and re-thinking education and learning on this major issue will also be key. Participatory research and co-learning will thus be central in this event.

For the first time, the Summit will be held in Latin America, enabling a spotlight on the Tropics, where phosphorus sustainability is a big concern. While significant progress on phosphorus sustainability has been made in Europe and North America, SPS 2018 will also explicitly focus on regional challenges and opportunities in Latin America, Africa, Asia & the Pacific.

SPS 2018 will take place immediately after the 21st World Congress of Soil Science (Rio de Janeiro from 12th – 17th August 2018) where the sustainable use of soils, including phosphorus fertilization, will be the primary focus. You will therefore have the opportunity to attend both events.

The location of the Summit, Brasilia, is the capital of Brazil: head office of the federal district government with a high quality of life. The capital is located in the Center West of the country, known as Central Plateau.

Brasilia is a distinguished city. The architecture, unique in the world, makes the city one of the largest open-air collections of modern architecture. An extraordinary project that gave the pilot plan of Brasilia the status of World Patrimony of Humanity. The city has numerous tourist attractions, such as the JK Bridge, Three Power Square, Planalto and Alvorada Palace, Paranoá Lake, Brasilia Cathedral, Federal Supreme Court, Museums, Ministries, 84 Embassies, Parks, among many other attractions.

Brasilia is surrounded by an expressive agricultural area where different crops are cultivated. It is a good example of agriculture in Cerrado and offers the opportunity for after-meeting technical trips.

When it comes to congress and meetings, Brazil is the ideal place excellent infrastructure, cutting-edge scientific research, and, a multi-cultural and ethnically diverse population. Finally, Brazil’s large territory comprises diverse ecosystems, a rich habitat for many animals and plant species.

SPS 2018 will be hosted by Embrapa, Brazil’s national agricultural research corporation, within the Ministry of Agriculture, Livestock and Food Supply.

Mapping the legacy P in Brazilian croplands under fertilizer usage for long time

Paulo S. Pavinato - College of Agriculture Luiz de Queiroz - ESALQ/USP. Av. Pádua Dias, 11. Piracicaba-SP. Brazil. CEP 13418-900; Paul J. A. Withers - School of Environment, Natural Resources and Geography, Bangor University, LL57 2UW, Bangor, UK; Davey Jones - Environment Centre Wales (Ecosystems & Environment, 2nd floor), Bangor University, LL57 2UW, Bangor, UK.

A major economic and environmental issue has being sentenced as the expansion of Brazilian agriculture in the coming decades for world food supply, increasing in this way the fertilizer requirement for higher agricultural output. Long-term field experiments have shown that a large proportion (>70%) of the surplus P added to Brazilian soils in fertilizers remains in forms not readily available for crops (legacy P). The use of this legacy P is potentially attractive because it provides financial savings on inputs of P fertilizers, reduces pressure on PR reserves and reduces the risk of water eutrophication. We aimed here to map the spatial distribution of total native P and the legacy P in Brazilian soils over the last five decades and estimate the potential use of it by crops. Mapping the original total P levels was based on the real values observed in the reports of exploratory projects developed in 1960-1970s (EMBRAPA) considering the observations in the surface layer, 0 - 30 cm (A horizon). In these reports it was possible to collect 1579 distinct points all over Brazil considering the total P (P₂O₅). To extrapolate the values for all over Brazil it was run a linear correlation between total P versus: clay content, C content, iron oxide (Fe₂O₃) and aluminum oxide (Al2O3) The best result was for Fe₂O₃ (0.63), being chosen to estimate the total P values for the other regions. It was considered the real values of Fe₂O₃ content observed in 3701 points obtained by RADAM Brazil project and other regional surveys. Maps of the spatial distribution of legacy P and the implications of this on the P balance were made here considering the main crop of each area, the time of cultivation and the amount of P added via fertilizer minus the export by crops harvested.

Rock reserves; P remaining in the soil; improving P efficiency.

Some Myths and Facts about the Use of Phosphorus in Agriculture

Luis Prochnow; Norman Chien

Phosphorus (P) is one of the key nutrients for plant nutrition. Fertilizing with P is seen as of low efficiency as related to nitrogen (N) and potassium (K). In reason of the complexity of soil reactions and the variety of options to increase the P availability for crops, many agronomic management technical issues are controversial leading to discussions and myths that already have clarification by science. The intention of this paper is to discuss or raise some of the main aspects related to myths and facts about the topic. Questions as follows will be objectively discussed: (1) May we transfer the sufficiency levels of P obtained in conventional agriculture to no-till?; (2) Are high contents of P in PR for direct application desirable?; (3) Is it necessary to always have high water solubility in totally acidulated P fertilizers?; (4) Is P localized better than P broadcasted?; (5) Can legacy P be used as to decrease the future needs of phosphate fertilizer in the tropics?; (6) Does integrating grass and grain crops increase P availability in the soil system?; (7) Is P from fertilizers really less efficient than N and K? The clear definition of correct answers to the questions above will bring higher effectiveness in the use of P in agriculture.

P Use Efficiency, P Sources, P Availability, P Use in Agriculture

Legacy soil P availability as affected by fertilizer and tillage management practices

Luiz Eduardo Zancanaro de Oliveira Rafael de Souza Nunes Djalma Martinhão Gomes de Sousa

Legacy soil phosphorus (P) is an important source of nutrient to crops, especially in areas where P application rates far exceed outputs in harvested products during years. This is a common practice in central Brazil, where P pool is a valuable resource that can be exploited by farmers. In order to investigate how P source and tillage practices affect legacy P bioavailability and plant uptake, an experiment was cultivated during four years with maize (Zea mays) under no-till (NT) or conventional tillage (CT) with no P inputs in a very clayey Oxisol in Brazilian Cerrado. P nutrition relied only on the residual soil P pool created after 17 years of cultivation of annual crops, fertilized with 35 kg of P ha-1 yr-1 as triple superphosphate (TSP) or reactive rock phosphate (RRF), band applied or broadcast. The experiment consisted in 8 treatments with 3 replicates organized in a randomized block design. Soil samples were taken at the depths 0-2.5 cm; 2.5-5 cm; 5-10 cm; 10-20 cm and 20-30 cm before and after the non-fertilized phase, from which total inorganic P (Pi) and soil density were evaluated. On average, maize yield was higher in NT, especially where residual P was RRF derived, in which case crop production was 25% greater, corresponding to a 27% greater total Pi offtake in the 0-30 cm layer, in comparison with the water soluble fertilizer. Plants took up the majority of P from surface layers in NT, especially at broadcast application. In TSP area, that occur up to 10 cm deep, while in previously RRF fertilized soils, P nutrition was concealed to the first five centimeters, probably due to slow solubilizing and releasing of phosphate that continues to happen years after its application under NT, benefiting crop yields.

Legacy P, no-till, P source

Prospects for Regional Gains in Phosphorus Efficiency for Future Global Food Security

Paul J A Withers - Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK

Regional and global food security is under continuing threat from environmental (e.g. climate change), resource (e.g. water, phosphorus (P) scarcity) and market (e.g. price volatility) stresses and shocks. Phosphorus (P) has also become a serious and costly pollutant of aquatic ecosystems due to the inefficient use of manufactured reactive P in the food chain and subsequent leakage to inland and coastal waters. Phosphorus use in the food system must therefore become more efficient, sustainable and resilient to ensure food and water security in the future. Security can be defined as when food system stakeholders have sufficient access to P to ensure soils are fertile, agriculture is productive, people have sufficient nutritious food, and rivers, lakes and oceans are clean (RePhoKUs, 2018). Inefficiencies of P use occur at both the field and farm scale and regionally, and these inefficiencies need to be addressed through collective transformative actions by all stakeholders (producers and consumers).

Different metrics of agronomic and environmental efficiency are useful to monitor the inputs, outputs and losses of P in the food system (Garnett et al., 2015), and a 5R P stewardship strategy (1R:Realign P inputs, 2R:Reduce P losses, 3R:Recycle P in bio-resources, 4R:Recover P in wastes, and 5R:Redefine P in food; Withers et al., 2015) has been developed to facilitate gains in P efficiency and sustainability. Examples of 5R management options in different regions are presented. Animal production cycles are less efficient than crop production cycles emphasizing the power of dietary choice in defining efficiency boundaries. Maximum gains in efficiency are likely to occur through lowering inputs whilst maintaining outputs and minimising losses. Circularisation and minimisation are therefore key concepts in regional drives towards P sustainability (Withers at al., 2018). Building resilience in food production cycles ultimately relies on becoming leaner but allowing a little slack in the system to cater for the unforeseen, and may require fundamental shifts in consumer behaviour to reduce environmental footprints!

Landscape features affect phosphorus fixation and availability in soils of the semiarid Pampa, Argentina.

Lucila Álvarez, Magdalena Torroba, Germán Morazzo, Elke Noellemeyer

Phosphorus (P) is a limiting nutrient in most agricultural soils, and its availability depends strongly on soil properties. The amounts of calcium (Ca) and carbonates (CaCO3) as well as iron (Fe) and aluminium (Al) are important in P-fixation; the distribution of these elements changes according to parent material and topographic position. This highlights the importance of understanding these processes for site-specific P management in order to improve the efficiency of P-fertilizer applications. We studied the distribution of inorganic P forms along toposequences in the two main agricultural areas of the Central Semiarid Region of Argentina, the Sandy Plain and the Calcareous Plain. P-Ca was the main fraction in both sites. The most labile forms were higher in Sandy Plain, but the main differences were in P-Ca which was significantly higher in Calcareous Plain and in P-Fe/Al which was significantly higher in Sandy Plain. Based on significance of regressions analyses, the results showed that in Sandy Plain solution-P was explained by P-Ca but not by P-Fe/Al, which could indicate P fixation into Fe/Al minerals. Whereas in Calcareous Plain, P-Fe/Al, but not by P-Ca, determined solution-P, highlighting the importance of Ca in P fixation. The main factors controlling P availability were Ca, CaCO3, total Carbon and pH. The strong relation of solution-P with total Carbon also indicated the importance of organic-P cycling on P availability. Ca and CaCO3 amounts were very important in Calcareous Plain affecting all fractions. However, in Sandy Plain CaCO3 showed an important effect in foot-slope only, due to the influence of a carbonated groundwater. In both sites the main effect of the landscape was in P-Ca which was higher in foot-slope positions, related with the presence of Ca and CaCO3. Managing P fertility in the landscape thus must consider these effects in order to minimize fertilizer P-fixation.

P-fixation, calcareous soils, topography, precision agriculture

Pasture management affects the phosphorus management strategies of sugarcane established following pasture

Amin Soltangheisi; Luiz Antonio Martinelli

Sugarcane is largely cultivated in Brazil in almost 9 Mha and it is expanding to new areas previously used for grain yield and cattle grazing due to higher demands for ethanol and sugar. These areas were originally forest and converted to pasturelands. Soil phosphorus (P) fractionation and grouping into chemically defined pools is useful for quantifying the fate of native and applied P in natural ecosystems and agroecosystems. This research work hypothesizes that the conversion of forest-pastureland-sugarcane can change the dynamics of P pools in the soil over time. This research was conducted in three different sites in Sorocaba, Manduri, and Brotas, SP. The areas have been used for dairy livestock for the last 30 years, after conversion from forest, one place with and two places without the addition of fertilizer and manure. The sugarcane trial was converted from pasture last year. Soil samples from the depths of 0-5, 5-10, and 10-20 from the forest, pasture, and sugarcane trials were collected and analyzed for chemical P fractionation. Soil P fractionation was conducted according to the methodology described by Hedley et al. (1982). P stocks followed the order of forest ˂ pasture ˂ sugarcane in all sites. Higher P stocks in pasture compared to forest can be related to the decomposition of roots of original vegetation. Phosphorus fertilizer addition in sugarcane trials resulted in the highest P stocks. Phosphorus addition enhanced only Pi (inorganic P) without any changes in Po (organic P) in comparison with pasture. The dominant changes of P stocks were observed in the soil surface layer (0-5 cm) as P is not mobile in these soils due to the high clay content. It seems that well-managed pasture does not need P addition at sugarcane establishment according to the high levels of labile P, compared to the low-input pastures.

Thanks to São Paulo Research Foundation (FAPESP), which supported the research and scholarship to the first author (Grant no. 2017/11332-5).

Land-use change; low input pasture; well-managed pasture

Phosphorus fractions and acid phosphatase activity in sugarcane fields after application of compost and inoculation of phosphate solubilizing bactéria

Antonio Marcos Miranda Silva, German Andres Estrada-Bonilla and Elke Jurandy Bran Nogueira Cardoso

Availability of phosphate in soil is dependent on the P mineralization and/or solubilization processes, for which the use of phosphate solubilizing bacteria (PSB) has been a biotechnological alternative in the soil-plant-microorganism system. Our objective was to evaluate the behavior of P fractions and acid phosphatase activity after application of compost produced with sugarcane industry residues (essentially filter cake and ashes) including PSB and co-inoculation in the fields. During composting, we added a rock phosphate either Araxá (AP) or Bayovar (BP) and maintained a control without P. The compost received the addition of Pseudomonas and Bacillus, while incubating the material for 60 days. In the field, we established six treatments receiving compost, two of them with AP, two with BP and two without P. Additionally, another treatment set was set up with the addition of PSB in the field. Finally, there was a positive control, which received only a synthetic fertilizer formulation routinely used in sugarcane. Six months afterwards, we collected soil samples from all treatments and proceeded chemical P fractionation. The inorganic plant available P fractions increased in the presence of PSB inoculation. In average, treatments receiving AP, presented from 14mg kg-1 (without) to 22mg kg-1 (with inoculation) in the Pi fraction extracted with an anion exchange resin. For treatments with BP (with or without inoculation) the mean Pi value was higher (26mg kg-1) than for AP, what may be associated with its greater solubility. The positive control showed an average value of 17mg kg-1 for this fraction. Acid phosphatase activity in the different treatments correlated with the amount of available P, and there were significant differences between those three treatments. We also found differences between PSB inoculated and non-inoculated treatments in compost with AP.

Enzymatic activity; composting

Evaluation of the kinetics of phosphorus and zinc release in fertilizers coated with materials obtained from renewable sources.

Fábio Plotegher, Ricardo Bortolleto-Santos, Vanderlei Roncato Júnior, Rafaela Ferraz Majaron, Vinícius Ferraz Majaron, Wagner Luiz Polito, Caue Ribeiro de Oliveira.

Brazil stands out worldwide as one of the largest producers in several crops of economic interest such as: soy, corn, sugar cane, coffee, citrus among others. One of the main factors that helped to leverage this productivity was a greater and better fertilization of the soils. However, as in the rest of South America, in Brazil most of the fertilizers used are models oriented to temperate soils, that is, they present high solubility, which causes great losses of the nutrients applied in the crops, as is the case of phosphate that ends up being immobilized in the soil due to the great concentration of iron and aluminum ions. One way around this problem is to use polymers from renewable resources to cover fertilizer granules, acting as a physical barrier, controlling the release of nutrients. Thus, this work proposed first, to use a zinc oxide suspension (ZnO) to cover granules of the commercial fertilizer monoammonium phosphate (MAP), so that each MAP granule can carry the micronutrient Zn to the soil, ensuring a better distribution of this element and secondly the use of a layer of zeins obtained from maize applied on the ZnO layer to act as a physical barrier and to control the release of both phosphate and ammonium from commercial fertilizer and from zinc. The results showed that there was adhesion between the deposited ZnO particles on the MAP granules and also the adhesion of the zeins on the whole system. The release tests on citric acid showed that there was delay in the release of both phosphate and ammonium as well as zinc. These results showed that it is possible that each fertilizer pellet carries a micronutrient with it facilitating the management of fertilization and that it is possible to use the zeins to control the release of nutrients in commercial fertilizers and this is an environmentally more correct option.

Release, Fertilizer, Zeins, Phosphate, Zinc.

The importance of spatially explicit data to inform phosphorus recycling between urban-rural and rural-rural divides

Geneviève S. Metson

One of the major challenges for increasing nutrient recycling is the potentially high cost and logistical complexity of transporting heavy organic waste to areas where there are crop nutrient needs. As such, it becomes crucial to determine exactly where sources of recyclable phosphorus are in relation to needs in order to make decisions about how to reconnect these areas. This will likely involve deciding on the optimal (often shortest) transport routes between areas of excess phosphorus to areas of crop demand, but there are many factors that must be considered to determine what is “optimal”. One key step towards imagining transportation configurations as well as how such recycling might intersect with other regional priorities is the creation of spatially-explicit phosphorus budgets. Here I demonstrate how such spatial analyses can help make progress towards phosphorus recycling in different contexts. I use urban examples from Phoenix USA, Sydney Australia, as well as national analyses in Sweden and Pakistan to show how moving from material flow analyses to mapping can result in novel and useful information for more sustainable phosphorus management. Maps can be used qualitatively to help diverse stakeholders examine complex issues of phosphorus management (or lack thereof) in a new light, while also allowing for quantitative estimates of transportation costs under different scenarios.

maps, transport, hotspots, recycling

Overcoming barriers - framework, insights and trends governing P-recycling

Ludwig Hermann - European Sustainable Phosphorus Platform & Proman Consulting

In response to the global challenge of excessive use of fossil materials from 1960 onwards and the simple fact that resources on our planet Earth are limited, recovery and recycling has gained momentum in recent years. In December 2015 the European Commission has adopted the Circular Economy (CE) Package aiming at reshaping the European economy from a linear to a circular pattern.

From the beginning of the 21st century, phosphorus and its derivatives have been the target of numerous research and innovation projects developing technical processes for producing dry fertilising products with high nutrient concentration facilitating transport and handling. These processes aim at complementing the direct application of millions of tons of organic residues which have been recycled locally in regions where the populations and/or livestock density generates much more nutrients than can be taken up and naturally removed by crops. However, despite the numerous technical recycling processes currently available on the market, their annual output does not exceed some 25,000 tons P in contrast to some 260 million tons mined from fossil resources.

A common place excuse would be to blame European and national regulators who have not fully adapted the legislative body to the requirements of the Circular Economy. This is partly true regarding national legislation: occasionally we have learned of national authorities refusing to declassify the waste-status and thus banning an impeccable recycling product from sales on its home market or a declined feed-in premium for biogas that recently has prevented a large biomethane investment in the Netherlands. In turn, the European Commission has delivered proposing a new Regulation on Fertilising Products (which is now stuck in the trilogue) and even reviewing the Nitrates Directive aiming at a precise definition of processes that could put an end to the manure status of a recycled product (e.g. mineral Ammonium Sulphate after N-stripping).

However, much more could be done by adopting legislation to make P-recycling mandatory as did Switzerland and Germany, albeit with transition periods of up to 15 years. Currently, we don’t see clear indicators of other countries to follow their example. Other supporting actions at the policy level could be tangible prices for emission rights, landfill taxes and – in a more holistic approach - shifting taxation from labour towards virgin material use, to name just a few. Recycling is typically more labour intensive and hampered by our taxation system. Finally, level playing fields would mean to account for externalities caused by pollutants in fossil raw materials and by the amounts of waste (phosphogypsum) created by traditional processes. To make things more complicated, the European Union, if adopting regulations in favour of a Circular Economy, should avoid legislative measures that have negative impacts on the fragile economies of Mediterranean and Middle East phosphate rock supply countries. The transition to a Circular Economy is complex and peppered with hidden pitfalls.

Another reason for the slow uptake of recycling processes and products may be the frequent disregard for market requirements. P-recycling processes were typically developed by small engineering companies, universities or research institutes, all not familiar with the needs of farmers and the usances of fertiliser markets. The fertiliser industry, even if present in joint research projects, frequently adopted an “observer” role without guiding developers towards convincing product design and marketing strategies. Hence, most processes were installed for their operations and maintenance cost savings and many products are sold at low prices or not sold at all. Start-ups focusing on product design and market development were the rare exception. One of these exceptions is Ostara: by appointing senior managers from fertiliser industry to the board Ostara managed to place its Crystal Green® product on niche markets for much higher prices than conventional fertilisers. Currently, new ventures aim at producing clean phosphoric acid or superior, fully water-soluble fertilisers with high nutrient concentrations and selling them to premium markets at a premium price.

Eventually, we will see a wide variety of products addressing different market segments: recycled agricultural and urban residues, with relevant organic carbon, relatively low in nutrients and high in impurities will be taken off locally by farmers in the neighbourhood and by specialized CE distributors operating at the lower end market. Safety of these products largely depends on upstream processes (e.g. avoiding excessive use of antibiotics and/or trace metals in livestock farming) and should be hygienised for pathogen elimination, if derived from excretions. At high-end markets, we will see well capitalised start-ups with professional product design, marketing and sales departments marketing their premium products. In addition, the fertiliser industry will play a role by integrating recycled raw materials to their processes and sell conventional fertilisers based on mixtures of primary and secondary raw materials. Clean secondary raw materials may be mixed with phosphate rock and produce cleaner fertilisers.

All-in-all we observe a steady, albeit slow development towards phosphate stewardship by recycling and more efficient use. A recent (not yet published) life cycle assessment (LCA) of primary and secondary phosphate based fertilising products has unveiled only two relevant impacts: human toxicity caused by heavy metals (cadmium, lead, zinc, copper, depending on the raw materials) and eutrophication. Eutrophication is, however, only marginally related to processing – the impact is mainly caused by fertiliser use and agricultural practice.

The train is moving and its moving in the right direction. Yet, the sustainable phosphorus community must remain in the driver’s cabin and continue to energize the movement.

Integrating climate drivers to the phosphorus transfer continuum and impacts

Per-Erik Mellander and ACP team - Teagasc, Agricultural Catchments Programme, Johnstown Castle Environmental Research Centre, County Wexford, Ireland

For a sustainable environment and food production, under the increasing pressures from a growing population and changing climate, we need efficient ways to manage phosphorus (P) and mitigate the losses to water. To achieve this challenge we need a comprehensive understanding of how climate drivers influence P along the transfer continuum and impacts, both over time and space, and for different catchment typologies.

Within the Irish Agricultural Catchments Programme P is monitored in sources, storage and delivery points in six intensively managed agricultural catchments under different settings. Source, mobilisation and transfer risks are assessed using methods facilitated by sub-hourly monitoring of P concentration and river discharge, monthly P concentrations in a network of piezometers and along the river network, mapping of soil P sources and landscape information from high resolution LiDAR Digital Elevation Models, soil and geophysical surveys.

It was found that: i) hydrology may overrides source pressure but P flux can be larger between years than between catchments, ii) mobilisation mechanisms, explained by soil chemistry, influenced leaching and loss to rivers at the small catchment scale, iii) despite an increased agricultural productivity a reduction of P transfer to rivers was identified, iv) apportionment of transfer pathways provided information on delivery times and “hidden trends”, v) temporal and spatial information on transfer pathways and delivery points can facilitate targeted mitigation measures, and vi) oceanic scale weather patterns influenced P loss to water to a varying degree in agricultural river catchments in NW Europe. Weather changes may override or indicate greater benefits of local management, and this will be catchment specific due to components such as mobilisation/transfer processes and hydrological connectivity. A clearer understanding of how climate drivers influence P loss differently in different catchment typologies is needed to reshape the thinking on future P management.

Adapting Sustainable Phosphorus Management to our Changing Climate

Heidi Peterson - International Plant Nutrition Institute, 15240 30th Street North, Stillwater, Minnesota, USA.

Phosphorus (P) is the key to life, and its sustainable management is critical for global food and water security. As the world’s population grows by a projected two billion people by 2050, global food production will need to increase considerably. As the demand increases for agricultural products, so does the demand for P fertilizer. Integrating the impacts of climate change, the variability involved, and its role in crop nutrient management, compounds the multi-dimensional challenge of increasing outputs in a sustainable manner to minimize the environmental impact while producing consistent and reliable wholesome products. Addressing this challenge requires a holistic approach to agricultural management which initiates with responsible crop nutrition and extends to include conservation practices implemented to reduce soil loss and improve soil health. Climate change models project regions that will undergo increased frequency of intense rainfall events as well as increased droughts or water deficits. These regions may experience increased P loss through soil erosion and surface runoff, and a reduction of plant available P. Warmer soil temperatures increase nutrient uptake when soil moisture is adequate. If there is an increase in plant available P without a change in nutrient application, P loadings to water bodies may increase. However, during periods of drought, crop root development is reduced, as is the ability to capture nutrients including P. Reductions in soil organic matter will result in a reduction of P mineralization, which provides a significant portion of the P available for crop use. Adopting sustainable P management which incorporates 4R nutrient stewardship practices can lessen these variable climate change impacts by applying P according to crop needs (right time), placing P correctly to maximize uptake (right place), at an amount which optimizes growth (right rate), and by using the most appropriate nutrient source (right source). Edge of field data has demonstrated the benefit of holistic agricultural management incorporating 4R nutrient stewardship practices with traditional conservation practices as a sustainable approach to meet global production needs in a changing climate, while minimizing environmental impacts.

Reuse of soil legacy and manure phosphorus can be fundamental to reduce non-point source phosphorus loading to Lake Eire

Zhang, T.Q., C.S. Tan, Y.T. Wang, B. Daneshfar, and T. Welacky

Agricultural lands have been deemed the primary non-point source of phosphorus (P) pollution causing the increased severity in toxic and nuisance algal blooms in Lake Erie over the past two decades. Efforts being made include implementation of BMPs (e.g. buffer strips, conservation tillage, and cover crops) to mitigate soil P loss and enhancement of monitoring exercise to evaluate BMP performance. While the BMPs are beneficial, researches have also found that their effects on reducing soil P loss can often be either process-specific or temporally and/or spatially limited. Considering P source supply the ultimate and critical factor controlling the soil P loss, legacy P that is already in soils and manure P that is an unavoidable by-product from livestock production require to be properly managed. Optimized utilization of manure P and legacy P in soils is considered fundamental and can be an effective and strategic measure to reach the goal of 40% P loading reduction from agricultural lands to Lake Erie by 2025. The presentation will attempt to review the nature of legacy P in soils of the watershed and the P in various animal manures as well as the effectiveness of their use in P loss reduction in several case studies.

Lake Erie, eutrophication, animal manure, legacy phosphorus

Cycle chains: Mapping phosphorus stakeholders by economy and ecology

Christopher Lyon, Julia Martin-Ortega, Miller Alonso Camargo-Valero, Dana Cordell, Brent Jacobs, Shane Rothwell, Paul Withers

Sustainable management of phosphorus (P) is vital for food systems resilience, and the delivery of critical ecosystem services such as clean water and biodiversity. Future global scarcity of P and potentially fluctuating costs threaten the security of the P-import dependent food system. The United Kingdom (UK) RePhoKUs project identifies that a key early step for managing the vulnerability of P systems is to understand which actors are influenced by, or in a position to improve, the resilience of these systems. To identify actors, we propose to apply to the UK context a novel stakeholder mapping methodology. Our method uses the conventional interest/power axis approach in a new way to integrate stakeholders from both the P value-chain and the P-ecological cycle. Value-chain based stakeholder mapping for P identifies stakeholders from mine to farm to fork thereby treating P as any other non-ecological commodity. This method limits stakeholders to those individuals or groups with a direct economic interest in P, e.g. mining sector, farmers, fertiliser companies, distributors, agri-businesses, and others. However, P is a key plant nutrient essential to life within the water-food-energy nexus, and has its own ecological cycle. Mapping stakeholders via the P-cycle identifies actors without a direct financial interest in P but nonetheless impacted by nutrient cycle dynamics, such as users of water bodies or landscapes impacted by abnormal P cycling, and members organisations such as NGOs, investors, communities, and others. We show how integrating value-chain and P–cycle stakeholder maps can inform the identification of short and long-term system vulnerabilities – and intervention points for resilience - depending on the location of the stakeholder in the chain or cycle. Furthermore, this approach potentially facilitates integration of P research with the broader social-ecological research agenda that includes climate change impacts and biodiversity decline.

food security, resilience, ecosystems, value-chains, methodology

Exploring the importance of teleconnections for phosphorus sustainability in Sweden’s food system strategy

Geneviève S. Metson, Tina-Simone Neset, Karin Eliasson, Michelle McCrackin

With limited financial, social, and political capital it can be difficult to set priorities related to investing in local or distant phosphorus sustainability endeavors to yield the best outcomes for food security and water quality for a particular community. Although it may be easier for a city to focus investment on improving local wastewater treatment or a country to strengthen national regulations on fertilizer application on agricultural lands, in an increasingly globalized world, that same city’s or country’s phosphorus security may be highly dependent on agricultural and waste management realities in other countries. For example, right now Sweden imports more P as food and feed than it does in the form of fertilizers, making its food and agricultural sector potentially more vulnerable to changes in other food production systems, notably in Brazil, Germany, the Netherlands, Norway, and Denmark. This means that understanding complex teleconnections is essential to meeting a community’s phosphorus sustainability goals. Here we examine how Sweden’s Food Strategy and Environmental Policy may be internally contradictory and incompatible with each other from a phosphorus security perspective. More specifically, we examine how meeting objectives for food production independence, increased export, and decreasing losses of P to waterways may interact with each other under different phosphorus efficiency, recycling, and trade scenarios. The strength and nature of these teleconnections, and their implications for phosphorus use and losses, are likely to be transformed under climate change and this must also be considered as a factor in to the criteria used to evaluate holistic food system options.

trade, Sweden, governance, scenarios

Industrial use of Phosphorus and its international trade dependency

Kazuyo Matsubae, Elizabeth Webeck, Tetsuya Nagasaka, Hisao Ohtake

Phosphorus (P) security is a particularly pressing issue because there is no alternative to phosphorus not only in agriculture but also in industrial sector. In order to improve P efficiency at the regional/country level, regional information/data are essential. In this study, international trade flow of elemental phosphorus was analyzed to determine the extent of the dependency of Asian countries on other countries to meet their phosphorus requirements. The results clarified that approximately 67% of the elemental phosphorus (also known as white phosphorus) provided by China and Vietnam for the international market in 2016 was consumed in Japan and India. Approximately three fourths of all the elemental phosphorus in the international trade market was consumed in five countries, Germany (20%), India (20%), Poland (14%), Japan (13%), and Brazil (10%). The automobile industry uses high-purity derivatives of elemental phosphorus to pretreat the surface of steel before the vehicles are painted, and they are also used to galvanize machine parts and as an etching agent in the semi-conductor industry. Japan imported 32 kt of phosphorus as elemental phosphorus from China in 2005, which accounted for 30% of Chinese exports, and 16 kt P from Vietnam in 2015. The high HHI for elemental phosphorus in Japan (0.95 in 2005 and 0.75 in 2016) shows that Japanese industry is almost totally reliant on China in 2005(Webeck, 2014a) and currently in Vietnam for its high-purity phosphorus.

In order to achieve sustainable phosphorus resource management on a global scale, it is necessary to recognize the importance of resource governance in Asia. There is a need to develop and tap into international collaborative networks for technology transfer pertaining to the recovery and recycling of phosphorus, the development of an Asia-wide market to trade secondary phosphorus resources, and the establishment and implementation of stringent regulations.

Elemental phosphorus, international trade, dependency, Herfindahl-Hirschman Index

Institutional frameworks and their role in sustainable management of phosphorus resources: a comparative assessment of EU and India

Madhuri Nanda, Arun Kansal

The planetary boundaries framework identifies and acknowledges the biophysical processes, which could be potential threats to human existence in coming decades . Phosphorus biogeochemical flows has been included among these nine planetary boundaries, along with nitrogen, while others are climate change, ozone depletion, land-system change, freshwater use, etc. Historically, developed countries have demonstrated proactive initiatives and pioneered the environmental movements, be it climate change, phasing of ODS, or others. However, developing countries have consistently lagged behind, even if the needs for change in these countries were far more pressing due to their inherent settings. Phosphorus biogeochemical cycle is positioned as yet another such phenomenon where historic trends are being experienced one more time. The current research work aims to uncover the motivation and drivers for European Union, like other developed countries, to build phosphorus resilience through stronger policy and institutional framework implemented over a period of time. It further attempts to assess the developing country challenges taking the case of India. The dialogues and engagement with stakeholders is built upon to unravel the challenges in policy shift towards sustainable phosphorus management, both in India and EU. While EU acknowledged their vulnerabilities to potential phosphorus scarcity early on, other countries like India are yet to raise their levels of national preparedness. This paper showcases an existing lack of dialogue and policy regime in India and provides learning opportunities for developing countries to strengthen their institutional support towards sound phosphorus governance. Recommendations emerging from this work would help other developing countries in a long way to enrich their discourse and strategically position themselves globally as phosphorus resilient economies.

India, EU, phosphorus governance, institutional framework

Spatially explicit use of phosphorus and related environmental impacts in Brazilian soybean production for European consumption

Karin Eliasson (1,2), Tina-Simone Neset (1,2), Geneviève S. Metson (2,3), Chris West (4), Simon Croft (4), Jonathan Green (4) 1 Department of Thematic Studies – Environmental Change, Linköping University, 581 83 Linköping, Sweden 2 Centre for Climate Science and Policy Research (CSPR), Linköping University, 581 83 Linköping, Sweden 3 Division of Theoretical Biology, IFM, Linköping University, 581 83 Linköping, Sweden 4 Stockholm Environment Institute (SEI), University of York, YO10 5NG, York, United Kingdom

The demand for food, and particularly livestock products, is projected to increase and so too is the use of natural resources for agricultural production, including phosphorus. In an increasingly globalised agricultural trade system, teleconnections become important in understanding the consequences of environmental and resource use associated with food consumption in one country are being displaced to producer countries. In addition to potentially displacing the nutrient related aquatic pollution associated with agriculture, a high share of food imports for a country might indicate increased vulnerability to changes in preconditions for agriculture in the country of production, such as access to mineral phosphorus fertilizers.

Soybeans have become an important part of industrial livestock production as a protein rich feed and understanding trade patterns between producer and consumer countries for soy is key to determining the changing impacts of agriculture on phosphorus security. Although phosphorus fertilizer application has decreased in Europe, imports of feed have increased. European countries import large amounts of soy from Brazil, the second largest producer of soybean in the world. Due to the phosphorus retention soil properties in Brazil, production requires high rates of phosphorus fertilizer application; however, this soil property also contributes to less nutrient loss. Although national patterns of trade and production have previously been highlighted, there remains a lack of high spatial resolution information on how specific consumption patterns in parts of Europe are connected to particular vulnerabilities and/or environmental consequences across specific Brazilian municipalities. This study explores how European soy consumption creates pressure on phosphorus resources and environmental impacts at the Brazilian municipal level. The results of this study contribute to making impacts of European consumption visible and to the research on European resource dependency. Initial results indicate significant differences in spatially explicit phosphorus use and potential environmental impacts caused by consumption in different European countries.

Phosphorus, soybean, Brazil, trade

POSTER SESSION

Effect of phosphate solubilizing microorganisms on common bean root development

Karla Vilaça Martins1; Ronaldo Batista Pinheiro2; Maicon Henrique Martins1; Adenir Antônio Martins Júnior1; Victor Barros Pacheco1 1University of Patos de Minas, 808 Major Gote St., Patos de Minas, 38.700-210, Brazil (karlavm@unipam.edu.br); 2Terrena Agronegócios, 1500 Rodrigo Castilho de Avelar Ave., Patos de Minas, 13.418-900, Brazil.

Tropical and subtropical soils are characterized by low levels of phosphorus in the available form to plants, limiting the yield of many crops. Different species of microorganisms are identified as capable increasing water use efficiency by plants or increasing the root system as well. The objective of this research was to evaluate the efficiency of the microorganism (Bacillus aryabhattai - BAYT) mixed with fertilizer on the development of root systems of the common bean plant. The study was carried in a greenhouse located in Patos de Minas, MG, Brazil. The experimental design consisted of randomized complete blocks with 7 treatments: [T1 - Control, T2 - Triple superphosphate (TSP - incorporated), T3 – TSP + BAYT (1 L ton-1) (incorporated), T4 - TSP + BAYT (5 L ton-1) (incorporated), T5 – TSP (surface), T6 - TSP + BAYT (1 L ton-1) (surface) and T7 - TSP + BAYT (5 L ton-1) (surface)], all with 4 replicates. The experimental unit consisted of a transparent plastic bottle of polyethylene terephthalate (PET) of1 L capacity. At the time of installation, a soil classified as Red Latosol of clayey texture was sieved through 2 mm, placed into the plastic bottle and irrigated with 5 mm of water with the aid of a watering can. Root dry matter and soil phosphorus content were evaluated 20 days after sowing. The root dry matter was on average, in T1 0.88 (c); T2 0.94 (bc); T3 1.13 (abc), T5 1.30 (ab); T6 1.36 (a); T4 1.44 (a) and T7 1.46 (a) g plant-1. Highest root dry matter value was observed in treatments where TSP was applied on the surface of the soil and when BAYT was mixed with the fertilizer. The phosphorus content in the soil when the fertilizers were applied to the surface was T1 2.73; T5 21.25; T6 27.43 and T7 26.32 mg dm-3. It is concluded that BAYT application increase the root dry matter of common bean plants. 

Fertilization; Phosphorus; Solubilization.

Kinetics of rock phosphate solubilization by organic acids in a stirred flow system

Jaqueline Maria do Nascimento; João Amaro Ferreira Vieira Netto; Rafael Vasconcelos Valadares; Leonardus Vergütz; Ivo Riberio da Silva; Maurício Dutra Costa

The use of rock phosphates (RPs) in agriculture is usually preceded by pre-treatments aiming at increasing RP solubility. Some microorganisms are able to excrete organic acids that release phosphorus (P) from stable forms, such as P-Ca, present in RP apatites. This work aimed at studying RP solubilization kinetics with different organic acids using a stirred flow technique. For this, 1.39 mg of P, as Araxá RP, was added to a Teflon chamber of a stirred flow system and a flux of 1 mL/min of the extraction solution was passed through for 150 min. The treatments were set up in a completely randomized design, with three replications, with split-plots in time. The extraction solutions were oxalic, citric, and gluconic acids at 5 and 10 mmol/L, and water, at pH 2 and 7. Solubilized P in the samples was determined every four min by colorimetric analyses. Oxalic acid caused greater RP solubilization compared to gluconic and citric acid at all sampling times. The maximum percentage of solubilized P, 43 %, was obtained with oxalic acid at 10 mmol/L. Oxalic acid was more efficient at solubilizing P from Araxá RP than water at pH 2 and 7. Our results showed that H+ acidity alone accounted for 34 % of RP solubilization, while Ca-organic acid complex formation and low pH, for 43 %. Thus, RP solubilization with organic acids must involve two concomitant processes: acidification and product removal by the formation of cation-organic acid complexes. 

oxalic acid; phosphorus; complexation; acidolysis.

Microbial diversity may affect the P availability in the soil through the mineralization 

Bruna Arruda, Fernando Dini Andreote

In general, microbial community affects phosphorus (P) cycling. In highly weathered tropical soils, P is not highly available, becoming mineralization of organic phosphorus a strategy for the P availability. The objective was to understand the dynamics of acid phosphatase activity (APA) under different soil microbial communities submitted to distinct amendment of P. The experiment was conducted in glasshouse, in a randomized block design, with four replications. The soil was submitted to a gradient of microbial community diversity: i) native soil; ii) sterilized soil; iii) soil dilution (10-3) inoculated in sterilized soil; and iv) heat treatment (80 ºC for one hour), and doses of P: 0, 40, 80 e 120 kg ha-1, applied as triple superphosphate. After the establishment of the microbial communities, 20 days after microbial diversity and P application, a soil sample was collected. The APA was assessed from fresh soil collected. Quantification data were submitted to ANOVA and regression adjustment. According to the regression adjustment, the P addition in the native soil increased APA, reaching the maximum value at 60 kg ha-1, and under higher level of P reduced APA. When the soil was submitted to a heat treatment, also high APA was observed, however presented an antagonist effect compared to the native soil, and the increase of P incremented the APA. On the other hand, low APA was observed in sterilized soil, with a negative response for the rates of P. When a diluted community was inoculated in the stylized soil a slight increase in APA was observed. Thus, a soil heat disturbance increased the P dependency for APA and the soil stylization reduced the mineralization potential to the soil.

Enzyme, Phosphorus, Dilution, Temperature

Microbiological mechanisms of P solubilization and desorption in hydroxyapatite and synthetic iron oxides 

AGUIAR, D. ; MELO DE, F.V.; KASCHUK, G.

Phosphorus (P) is considered a critical element in soils because it is adsorbed to the minerals, restricting its availability to the plants. In soils with high amounts of iron oxides, P adsorption may become irreversible given the characteristics of the bonds formed between P and Fe and Al oxides. This study aims to verify the effect and to study the mechanism of structural P release from hydroxyapatite and fixed P forms on goethite mediated by microorganisms. For this essay, goethite was previously synthesized, saturated with KH2PO4 and the surface complexes characterized by infrared. Sorption isotherms and pH envelopes were measured using the flow cell technique. Goethite and Hydroxyapatite (Sigma Aldrich-PA) sample were characterized by X-Ray Diffraction (XRD) with CαKαl with a wavelength of 0.178890 nm, for powder patters data were collected at 2θ from 5° to 50°angles and 2θ from 5° to 70°angles, respectively. To microbiological desorption were selected 5 heterotrophic microorganisms, each one cultivated in a liquid medium with extract glucose/dextrose at 30 ± 1°C in B.O.D., for 15 days. The treatments will consist of microorganism + hydroxyapatite; microorganism + goethite adsorbed with non-labile P; hydroxyapatite + organic acid; goethite adsorbed with non-labile P + organic acid. Desorption contents will be characterized by chromatography and Infrared methods.  For siderophore detection will be used chrome azurol S(CAS). Electric Potential and pH will be measured every 24 hours. All determinations will be made in triplicate and the data will be treated statistically using SPSS 23.0 software for Windows and Tukey test (p≤0,05).  We expect to clarify and explain P desorption describing the microbiological mechanisms and through Langmuir isotherm.

Desorption, Fe oxides, Solubilization, microrganisms, Phosphorous.

Phosphorus availability and corn growth in Oxisol fertilized with biochar and humic acid

Sara Dantas Rosa, Rimena Ramos Domingues, Bruno Paulo Moschini, Carlos Alberto Silva

Chicken manure biochar (CMB) and humic acid (HA) can change soil chemical properties and increase some nutrients availability, such as P, which improve nutrient acquisition by plants. The aim of study was to evaluate the effects of increasing CMB rates, combined or not with HA, on soil P availability, and corn nutrition and growth cultivated in a medium texture Oxisol. A 4x2 factorial scheme was adopted through the combination of four CMB rates: 0.25, 0.5, 1.00 and 2.00% w/w, with addition or not of 50 mg kg-1 C-HA, with three replications. Soil-treatments mixtures were incubated for 20 days, keeping moisture near 70% field capacity (FC). After incubation was determined P availability by Mehlich-1 for each treatment. In sequence, water was added to soil to reach moisture near 100% FC, which was maintained overnight to reach equilibrium between liquid and solid phase, and then soil solution was extracted by the Suolo Acqua® solution sampler to analyze soil solution P (SSP). Corn was sown and grown for 45 days in greenhouse conditions. Corn dry matter (DM) and accumulation of P (AcP) was determined. The data were subjected to analyses of variance and regression. SSP and soil available P contents increased over CMB rates, in soil treated or not with HA. The rate of 2% CMB increased SSP and P availability about 10 times as high as levels of 0.25% CMB. At the rate of 2% CMB, the addition of HA increased the SSP and soil P availability in relation to soil without HA. Shoot DM was not affected by CMB rates or  use of HA. Root and total DM, and shoot AcP were influenced only by CMB rates. The AcP in corn shoot increased over CMB rates. The use of CMB is a suitable strategy to increase SSP and P availability in the highly weathered Oxisol.

organic matter; humic substances; soil solution P; highly weathered soils

Phosphorus fractions and acid phosphatase activity in sugarcane fields after application of compost and inoculation of phosphate solubilizing bacteria

Antonio Marcos Miranda Silva, German Andres Estrada-Bonilla and Elke Jurandy Bran Nogueira Cardoso

Availability of phosphate in soil is dependent on the P mineralization and/or solubilization processes, for which the use of phosphate solubilizing bacteria (PSB) has been a biotechnological alternative in the soil-plant-microorganism system. Our objective was to evaluate the behavior of P fractions and acid phosphatase activity after application of compost produced with sugarcane industry residues (essentially filter cake and ashes) including PSB and co-inoculation in the fields. During composting, we added a rock phosphate either Araxá (AP) or Bayovar (BP) and maintained a control without P. The compost received the addition of Pseudomonas and Bacillus, while incubating the material for 60 days. In the field, we established six treatments receiving compost, two of them with AP, two with BP and two without P. Additionally, another treatment set was set up with the addition of PSB in the field. Finally, there was a positive control, which received only a synthetic fertilizer formulation routinely used in sugarcane. Six months afterwards, we collected soil samples from all treatments and proceeded chemical P fractionation. The inorganic plant available P fractions increased in the presence of PSB inoculation. In average, treatments receiving AP, presented from 14mg kg-1 (without) to 22mg kg-1 (with inoculation) in the Pi fraction extracted with an anion exchange resin. For treatments with BP (with or without inoculation) the mean Pi value was higher (26mg kg-1) than for AP, what may be associated with its greater solubility. The positive control showed an average value of 17mg kg-1 for this fraction. Acid phosphatase activity in the different treatments correlated with the amount of available P, and there were significant differences between those three treatments. We also found differences between PSB inoculated and non-inoculated treatments in compost with AP.

enzymatic activity

Rock phosphate solubilization by Penicillium islandicum in media with different nitrogen levels

Victor Hugo Araújo Bonduki, Ellen Maria Santana, Rafael Vasconcelos Valadares, Gilberto de Oliveira Mendes, Wendel Batista da Silveira, Maurício Dutra Costa

Phosphorus (P) release from rock phosphates (RPs) applied directly to the soil is generally low, hindering crop productivity. Thus, RP solubilizing microorganisms (PSM) are emerging as a viable alternative for RP solubilization prior to using RPs in agriculture. Since PSM are generally heterotrophic, microbial solubilization is dependent on the presence of organic substrates with adequate C/N ratios. Therefore, the objective of the present work was to determine N concentrations in the culture medium that favor RP solubilization by P. islandicum in a solid-state fermentation system with sugarcane bagasse. Sequential experiments were conducted in a completely randomized design, with three replications. The main factor studied was N availability in the medium, which varied from 0 to 0.247 g/L. Another experiment was conducted in which the fungus was previously cultivated in liquid Strasser medium with its original N concentration (0.247 g/L). Then, after seven days of cultivation at 30 °C, the whole mycelial biomass produced was transferred to a modified Strasser medium with decreased N concentration (0.012 g/L). Araxá RP, at 3 g/L, was used as a reference P source in all experiments. The treatment without N led to the solubilization of, approximately, 11 % of the RP after 10 days of incubation at 30 °C in the solid-stated fermentation system, while higher N levels led to the immobilization of P by P. islandicum. The pre-cultivation of the mycelial biomass and its subsequent transfer to a fresh liquid medium with lower N led to 30 % solubilization. Thus, fungal pre-cultivation with subsequent biomass transfer to N-depleted media is a promising technique to induce fungal RP solubilization.

C/N ratio, solid-state fermentation, sugarcane bagasse, phosphorus 

Soil phosphorus fractions in sugarcane under phosphate sources and filter cake association

Thais de Marchi Soares, Valdevan Rosendo dos Santos, Amin Soltangheisi, Wilfrand Ferney Bejarano Herrera, Gabriel Cato, Mathaus Mandro, Gabriel Novoletti, Henrique Coutinho Junqueira Franco, Oriel Kolln, André Cesar Vitti, Paulo Sergio Pavinato

Phosphate mineral fertilizers are widely used to ensure high productivity of the sugarcane in Brazil. The association of these fertilizers with organic sources such as filter cake (FC) can be beneficial once this material releases its P and other nutrients gradually and its use can increase mineral fertilizer efficiency, reducing the costs and avoid environmental problems from faster solubilization sources. This work aimed to evaluate the effect of soluble and reactive phosphate sources associated with FC on soil P fractions after two seasons. Field experiments were carried in two different areas: a) expansion area with very low soil P, sandy soil with low P adsorption, being cultivated with sugarcane for the first time; b) area with sugarcane for decades where test P level is medium, very clayey soil with high P adsorption capacity. The mineral sources used were triple superphosphate (TSP) and reactive phosphate (RP) at the rate of 90 and 180 kg ha-1 of P₂O₅, associated with the absence and presence of 10 Mg DM ha-1 of FC. Hedley’s P fractionation was performed in association with P K-edge XANES speciation in soil samples taken from 0-20 and 20-40 cm depth layers. In the situation ‘a’ TSP altered the labile and moderately labile P fractions in the layer 0-20 cm, especially in the presence of FC, increasing according to the P rate. On the other hand, RP application altered just the non-labile P in the same area. Filter cake alone was able to increase the labile P and decrease the non-labile P in the layer 20-40 cm in the situation ‘b’. Concluding, FC did not has a great interaction with RP (a cheap source) to keep more P available in the soil.

P organic source; Organic waste; Reactive phosphates; Solubility

Soil phosphorus, root distribution and soybean and corn yields resulting from long-term soil tillage systems and phosphate fertilization management

Rafael de Souza Nunes, Djalma Martinhão Gomes de Sousa, Wenceslau J. Goedert, Thomaz Adolpho

The proper absorption of phosphorus (P), growth and crop productivity in the long-term depends on the adoption of management practices that promote soil P bioavailability and its access by crop roots. We investigated P and root distribution in the soil profile and their effect on P uptake and soybean and corn growth and yields under different tillage systems (conventional - CT and no tillage - NT) and phosphate fertilization management (triple superphosphate - TSP or reactive phosphate rock - RPR, broadcast or band applied). The experiment was located at Cerrado region in a very clayey Oxisol, cultivated for 17 years with soybean and corn, receiving 35 kg ha-1 yr-1 of P. It was evaluated available P and root density distribution in depth, biomass production and P uptake by soybean and corn, as well as grain yield. CT promoted more homogeneous soil P distribution while in NT there was a strong gradient in depth, with nutrient accumulation in the fertilizer application zone. The average contents of P in the profile were similar for the two tillage systems and fertilizer application methods, but higher for TSP in relation to RPR. Root distribution of soybean and corn showed a strong relationship with soil P distribution, except for soybean growing under CT. The production of biomass, P uptake and grain yield of soybean in CT was influenced by phosphate fertilization management and presented lower performance than in NT, which did not occur for corn possibly due to higher P uptake efficiency of this crop compared to that of soybean. Greater stratification of soil P and roots of soybean and corn in NT does not represent any limitation on the nutrient uptake and yield of these crops. The influence of soil tillage management and phosphate fertilization is most evident in soybean as compared to corn.

broadcast application, band application, superphosphate, reactive phosphate rock, conventional tillage, no-tillage.

Nutrient management valuation in an agricultural watershed in the Upper Pantanal, Brazil. 

Felipe Siqueira Pacheco, Luciene Gomes, Karina Tôsto, Marcela Miranda, Simoni Loverde-Oliveira, Dhonatan Diego Pessi, Hans Van Grinsven, Christopher Cox, Jean Ometto

Agricultural systems play a key role in achieving the Sustainable Development Goals due in view of the challenge to produce enough food to feed a population, expected to reach nine million people by 2050. More efficient and sustainable nutrient use in Agriculture is an important step for the dual challenge to increase production while minimizing threats to natural ecosystems and depletion of resources. In this study, we developed a nutrient balance methodological approach (for phosphorus and nitrogen) to value nutrient use practices in crop and livestock systems of the Vermelho River basin in the Mato Grosso state`s Upper Pantanal, investigating options for improving nutrient use efficiency and quantifying the multiple costs and benefits of nutrient (N and P) use for ecosystems, human health and climate. Phosphorus (P) budgets in crop soils are positive while those in pasture soil tend to be negative. The positive values in the crop soils is due to the high input of P through mineral fertilizer and to the high P-sorbing capacity of the soils. The negative values in the pasture land caused by removal of animal products without nutrient replacement. Most of the nitrogen (N) inputs in the crop soil comes from biological nitrogen fixation associated with soybean cultivation. The nitrogen use efficiency in the region is around 0.9 which represents a critical value between the desirable range (0.5 to 0.9) and the risk of soil nutrient depletion (>0.9). The first estimates of the direct economic benefit of N in agricultural production is about 37 million dollars per year and is lower than the annual societal cost of pollution which is about 18 million dollars for human health and 58 million dollars for ecosystems. However, when we consider the costs and benefits of P, the total direct economic benefit increased to about 93 million dollars and is higher than the annual cost of pollution which is about 86 million dollars.

nutrient use efficiency, Upper Pantanal, crop soil, pasture soil

Effects in the soybean yields response due coated phosphorus applied

Aline de Almeida Vasconcelos1; Ronaldo Batista Pinheiro1; Karla Vilaça Martins2; Maicon Henrique Martins2; Adenir Antônio Martins Júnior2; Victor Barros Pacheco1 1Terrena Agronegócios, 1500 Rodrigo Castilho de Avelar Ave., Patos de Minas, 13.418-900, Brazil (aline.vasconcelos@terrenaagro.com.br); 2University of Patos de Minas, 808 Major Gote St., Patos de Minas, 38.700-210, Brazil

In this abstract, we report the results of studies on the phosphorus (P) availability and the soybean yields response for coated and uncoated phosphorus (monoammonium phosphate fertilizers - MAP) applied at five increasing doses (0, 150, 200, 250 and 300 kg ha-1) in oxide tropical soils, Patos de Minas, Minas Gerais state, Brazil. We evaluated, P leaf content in the soybean blooming stage by digested with a nitric-perchloric solution, and the P in the extract was determined by the colorimetric ascorbic acid method, soil P availability was determined using anion-exchange resin method and the and soybean yields was evaluated via manual harvest. Despite important information attest to the low effectiveness for P uptake of plant growth at the beginning plant growth stages, MAP coated not limited the absorption efficiency due P slow-release, the different doses of P treatments presented same magnitude of content in the leaves. Several studies indicate higher phosphorus adsorption highly weathered soils, however phosphorus coated provided higher available soil phosphorus content when compared with uncoated phosphorus. In the current study, the coated fertilizer improve 19% and 34% P availability than uncoated MAP and without fertilizer (0 kg ha-1), respectively. The dose of 150 kg ha-1with coated Map presented higher productivity (97,8 sc ha-1) while the dose of 200 kg ha-1with uncoated presented the lower productivity (74,9 sc ha-1). Overall, the coating MAP resulted in greater P availability.

Glycine max (L.) Merrill; Fertilization; Phosphorus.

Geopolitics of phosphorus in the light of future conflicts

Dr. Tina-Simone Neset Department of Thematic Studies – Environmental Change, Centre for Climate Science and Policy Research, Linköping University

Estimates of phosphate rock reserves have been object to the scientific debate for the last decade, caused by a significant variation for several countries, with the most pronounced increase due to the revision of estimates for Morocco and Western Sahara in 2010/2011. This development raised the total global estimates by more than 4 times from 2009 to 2010, and created an unprecedented geographical distribution of reserves with over 70% of global reserves being governed by Morocco and Western Sahara alone. Based on the most recent USGS (2018) estimates, the ten countries with the largest share of reserves control 94% of global reserves.

The issue of global governance of a resource that modern food production is highly dependent on, raises the question of current and future political stability in these countries, as well as for regions where mining and processing is located. Given the current reserve estimates and production rate, the number of countries and their contribution to the global phosphorus supply is expected to change until the end of this century, probably enhanced by population growth and an increased demand for fertilizer in food production globally. In this study, we apply country-level risk estimates for the period up to 2100 of predicted probability of conflict for each of these countries. Probability of conflict is estimated based on a wide set of indicators, and modelled for each of the five Shared Socio-Economic Pathways (SSPs). This assessment allows for new perspectives on the geopolitics of phosphorus from a human and national security perspective, and addresses questions on the role of conflicts and food security as well as the geography of food production and consumption for the coming decades.

geopolitics, phosphate rock reserves, future conflict, shared socio-economic pathways

A phosphorus index for conservation agriculture systems in Southern Brazil

Gabriel Democh Goularte, Nerilde Favaretto, Gabriel Barth and Aline Fachin Martini

Phosphorus (P) transport from agricultural fields to water is a worldwide concern, so it is important to develop tools to help farmers and field staff for best management practices. The P-index combines factors related to P transport and P source to estimate a scale of vulnerability of P loss from agricultural fields. The objective of this work was to develop a P-index (field scale) adjusted with principal component analysis (PCA). Simulated rainfall was applied in 10 agricultural fields with slope from 6 to 17% and different soil and crop management in Campos Gerais region, Southern Brazil. Three observations were made for each field (n = 30). The observations were separated into two groups: main group (n = 20) and test group (n = 10). For the analysis of main components, it was considered the following field attributes: dry mass of cover crop residue (CCR), organic carbon (OC), visual evaluation of soil structure (VESS), soil test P (STP) and clay content. The results were correlated with runoff coefficient (RC), final infiltration rate (FIR), concentration and losses to total sediment (TS), total P (TP), soluble P (PSOL), particulate P (PPAR) and bioavailable P (PBIO). Component 1 explained 49.3% of the total variation demonstrating dependence on RCC, OC, STP and VESS. Component 1 correlated with increase of RC, reduction of FIR, increase of TS and PPAR concentrations and losses and increase of TP losses. This result was interpreted as “high risk of PPAR transport”. Component 2 explained 21.3% of the total variation with strong dependence on OC, STP and clay content. Component 2 correlated with increased PSOL and PBIO concentrations and losses and with reduction of TS and was interpreted as “high risk of PSOL transport”. The components 1 and 2 were separated in four classes of vulnerability: low, medium, high and very high. The high similarity of the results from the main group (n = 20) and test group (n = 10) demonstrated the efficiency of the developed model.

P-index, field attributes, no-till, water pollution

A simplified model for Phosphorus Thresholds in soils receiving pig slurry in Santa Catarina State, Brazil

Luciano Colpo Gatiboni, Daniel João Dall’Orsoletta, Djalma Eugenio Schmidt, Thomas Jot Smyth, Rodrigo da Silveira Nicoloso

Santa Catarina State is the largest pork producer in Brazil an is carried out on small farms (<20ha) with steep slopes (20 to 40%) where pig slurry is applied to the soil surface as fertilizer. Until 2014 the States’ environmental legislation allowed the application of a maximum rate of 50 m3/ha/year of pig slurry and did not consider important factors such as the phosphorus (P) in the waste, the P sorption capacity of the soil, the removal of P by plants and the use of other P sources. After 2014 the legislation was improved establishing a P-threshold (P-thr), which is the maximum environmentally safe P concentration in the soil, beyond which the soil is a source of P to the environment. The model was adjusted considering that soils with higher clay content sorb more P and could receive larger rates of manure: P-thr=40+Clay% (where P-thr is the maximum content of P by the Mehlich-1, in mg/dm3, in the 0-10cm soil layer, and clay% is the clay content of the soil in percentage). This method has been used since then, and if a soil has a P content above the P-thr, no inorganic or organic P application to the soil is allowed. However, the developed method infers only about the soil sorption capacity, and does not consider the transport factors contributing to P loss by runoff. Thus, two field experiments were carried out using soils with contrasting textures (22 and 64% clay), testing three land slopes (up to 35%) and four rates of pig slurry (up to 440 kg/ha/year P₂O₅) in bermudagrass pastures. In the sandy loam soil, the amount of P lost by runoff is less dependent on the slope due to the higher water infiltration of the soil, and increasing the slope from 15 to 35% increased by 37% the P lost into runoff. Conversely, in the clayey soil, increasing the slope from 10 to 30% increased by 95% the P lost into runoff. Thus, we are proposing to include the land slope in the model: P-thr=(55+Clay%)-(0.03*Clay%*Slo%), where Slo% is the land slope in percentage (R2=0.96).

phosphorus, eutrophication, P-threshold, animal wastes

CAN PHOSPHORUS BE REMOVED INTO A MODIFIED LUDZACK ETTINGER SYSTEM?

Camila Ester Hollas; Angélica Chini; Fabiane Goldschmidt Antes; Marcelo Bortoli; Airton Kunz

Swine production is an important livestock sector worldwide. The activity has a high ability to impact the environment, mainly due to the large volume of waste generated. Phosphorus (P) and ammoniacal nitrogen are present in these effluents in relatively high concentrations and in regions with intensive swine production; the soil support capacity usually exceeded the species concentration in effluents. Biological or physico-chemical processes can be employed for these effluents treatment. The modified Ludzack-Ettinger (MLE) system is applied for the removal of nitrogen from this kind of wastewater. However, there is a lack of studies using MLE processes for concomitant P removal, especially for effluents with high P concentrations that was the main objective of this study. The swine manure was pre-treated in a static sieve of rotating brushes followed by solid-liquid separation with hydraulic retention time (HRT) of 30 minutes for the removal of solids. This effluent was used to feed the MLE process, operating with a HRT of 4.6 days. The system was monitored during 52 days and in this period the average of P concentration in effluent of the MLE was 16.8 ± 3.1 mg L-1, which corresponds to 49 ± 0.07% of removal. Additionally, the system presented 91.84 ± 6.2% of efficiency in nitrogen removal and 74.86 ± 6.3% of organic carbon removal. The removal of P can be attributed to the generation of calcium phosphate, since the reduction of calcium corresponded to the stoichiometric Ca:P molar ratio. Also the pH in the nitrifying and denitrifying reactors was 8.14 ± 0.23, which allows precipitation of Ca₃(PO4)2. The P removed from liquid remained in sludge and therefore these fractions needs to be properly managed (used as fertilizer or in composting, for example).

Treatment; pollution; swine wastewater

Phosphorus balance in an urban tropical shallow lake: implications for eutrophication management.

Marcela Miranda, Marcelo M. Marinho, Natália Noyma, Maria Fernanda A. Soares, Vera L. Huszar, Frank van Oosterhout, Miquel Lürling, Jean Ometto, Felipe S. Pacheco

Eutrophication of aquatic ecosystems is one of the major challenges for inland water managers. -Phosphorus (P) is considered the main limiting factor for phytoplankton in most of the inland waters. When in excess, P can stimulate the overgrowth of primary producers. The reduction of P external loads is the main action to control eutrophication in lakes. An efficient system analysis, evaluating nutrient inputs and outputs is fundamental to indicate better strategies for system recuperation. P balance of an urban tropical shallow lake was calculated based on external inputs (direct precipitation, runoff, fountain, well and birds), and a single output (outflow). We also consider the deposition of P in the sediment as an output and the release of P from the sediment to the water column (internal loading) as an input. The total input of external P into the lake is 11.0 g. P m-2 year-1, while the outflow is 12.6 g P m-2 year-1. The major contribution to the P input was from the birds (78% of all inputs or 9.8 g P m-2 year-1). The highest P output from the system was to the sediment (12.5 g P m-2 year-1) which represents 99.76%. However, a part of the sedimented P returns to the water column (1.1 g P m-2 year-1). Thus, the amount of 11.6 g P m-2 year-1 is permanently lost to the sediment. System analysis showed that the contribution of P from external and internal sources are 78% and 8.8%, respectively. Therefore, for an efficient measure for mitigation of eutrophication and cyanobacteria bloom of this system, measurements should focus on the reduction of the external inputs by controlling birds living nearby the lake and internal loading by trapping the P to the sediment.

Eutrophication. System Analysis . Lake restoration

Phosphorus Removal and Recovery in a Field Swine Manure Treatment System

Fabiane Goldschmidt Antes; Lidimara Suzin; Gizelle Cristina Bedendo; Marcelo Bortoli; Airton Kunz

Livestock manure has good fertilizer potential due to the presence of high concentrations of nutrients as nitrogen and phosphorus. On the other hand, in concentrated feeding operations, the effluents generated from livestock production must be properly managed to avoid negative environmental impacts. In this sense, a phosphorus removal unit (PU) based on calcium phosphate crystallization was installed as the final step in a swine manure treatment system. Swine manure is previously treated by chemical flocculation, anaerobic digestion and nitrification (activated sludge) processes for carbon and ammoniacal nitrogen removal and the effluent is treated in PU. This effluent rich in phosphorus is mixed with hydrated lime (10% (m/v) Ca(OH)2 solution) in a flow system. A settling tank is used for phases separation. Then, the supernatant is collected in a reservoir for reusable water and the sludge goes to a drying bed. The performance of PU was evaluated during 51 days after its installation. During this period, the average phosphorus concentration in affluent was 80.9 ± 37.3 mg L-1 while the concentration in treated effluent was 3.5 ± 0.8 mg L-1, corresponding to an efficiency of phosphorus removal higher than 92%. This result is in accordance with local regulations for effluents disposal in water bodies. The use of hydrated lime for precipitation of phosphorus was also suitable to reduce total suspended solids and turbidity of the final effluent. The effluent can be discarded in a water body or reused, for example, in cleaning of installations. Additionally, the sludge produced is rich in phosphorus (5.71 ± 1.24%) and can be used as fertilizer, in animal feeding or other applications. The proposed treatment is relatively easy to be implemented in field operations, and the cost of hydrated lime has relatively low impact in the overall treatment costs.

Pollution; treatment; swine wastewater