Thursday 11^th December 2025

On Thursday there will be separate presentations for those interested in either crop nutrition or fertiliser production. The crop nutrition abstracts are shown first, with the production ones below.

AGRONOMIC TOPICS

Soil phosphorus mobilisation: challenges and opportunities

Phil Haygarth, Lancaster University, UK

In the few decades since the commercialisation and global distribution of rock phosphate, it has had a significant positive influence on world agriculture.  However, there are major challenges that lie ahead, around understanding and enhancing phosphorus mobilisation through soil, and in to crops, which is mostly an inefficient transfer.  Much of the phosphorus that is applied to soil is stored away in immobile (‘organic’ and other) forms, with only a small proportion seeming to be ‘available’ for uptake for plant benefits.   Typically, in England and Wales, the Olsen ‘available’ P in agricultural soils varies from only a few percent (3-6% in two examples to be presented) of the total soil P, yet immobile organic compounds of P are locked up in soils and comprise ca. 40-70% of total, much more than ‘available’ P. 

We assembled a global database of soil plant available phosphorus and from this, estimated global phosphorus stocks in croplands and grasslands that are not readily available to plants.  Remarkably, a large amount of phosphorus is not readily available in World soils, and this represents globally 32–41% of the 2020 estimated geologic phosphorus reserves.  If we could use this to better effect, it would be equivalent to representing 146–186 years of the 2020 mass of phosphorus fertiliser applied annually.  Additionally, we have determined that globally 73% of the world agricultural land is below optimum P threshold, with much of the Global north in excess, and much of Africa depleted.  The challenges ahead lie in balancing and regulating the inputs of new phosphorus with recycled phosphorus forms, such as animal manures, and, critically seeking plants that can better access the normally ‘immobile’ forms.   

Sustainable phosphorus fertilisation requires balancing crop production and water quality objectives

Maarten van Doorn, Nutrient Management Institute, the Netherlands

This paper addresses the challenge to produce food while safeguarding surface water quality objectives. Especially in regions with high livestock densities, (historic) phosphorus (P) applications exceed(ed) crop demand leading to the build-up of soil P. While this has increased yields, it has also led to widespread surface water eutrophication.

This study substantiates how environmental thresholds can be incorporated into fertilisation recommendations. Such thresholds require insight into both the amount of plant available P in a soil (P quantity) and the directly available P fraction that is prone to leaching (P intensity), as well as the degree of hydrological connectivity between fields and surface waters. Most countries only
have one measure to assess agronomic plant available soil P levels. The outcome of such soil tests are translated to fertiliser recommendations solely based on (historic) crop response trials. Generally no information is available on the directly available P fraction that is prone to leaching. Subsequently, the risk of leaching is not taken into account.

We show that the P binding capacity of the soil is pivotal in understanding how a P quantity measure provides information on both available soil P for the crop and the P fraction that is prone to leaching. In addition, we show that the P binding capacity is a soil property that can be predicted well through digital soil mapping using data from general soil databases. Combining the soils binding capacity and a measure for P quantity gives insight in the extent to which the soil has
been saturated with P (P saturation degree). The P saturation degree is in turn related to the P fraction that is prone to leaching. Combining data from standard soil P tests and digital soil mapping thus provides a powerful framework to gain insight in P quantity-intensity relations at high spatial resolution.

Using the Netherlands as a case study, we demonstrate how information on soil P quantity-intensity relations can be used to derive environmental soil P thresholds. Specifically, we propose environmental P intensity thresholds of 0.1 to 0.3 mg ortho-P/l in soil solution, depending on hydrological connectivity. Both agronomic and environmental implications of using these
thresholds are discussed.

Our findings highlight the need to shift the rationale of fertiliser recommendations from optimising soils for crop production to producing food within environmental boundaries. This also implies that some soils are more suitable for intensive crop production than others.

Mitigation of Greenhouse Gas Emissions from Soils by Enhancing the N2O to N2 Reduction Pathway

Catherine Henault, INRAE, France

The mitigation of greenhouse gas (GHG) emissions, particularly nitrous oxide (N₂O) from agricultural soils, is crucial given the unprecedented atmospheric concentrations of GHGs such as carbon dioxide (CO₂), methane (CH₄), and N₂O, which continue to rise rapidly since industrialization. Agricultural soils represent a major source of N₂O, a potent greenhouse gas with a significant global warming potential. Over time, we explore the evolution and application of biotechnical strategies aimed at mitigating N₂O emissions in soils. Here, we presented two key mitigation approaches, which are: (1) climatic liming which involves liming addition to attain soil pH of 6.8, and (2) inoculation of legumes with rhizobial strains harboring nosZ genes, known to encode for N₂O reductase. These approaches were based on prior research conducted to demonstrate their respective efficacy in stimulating N₂O conversion to N₂ in soil. Additionally, our findings from climatic liming suggested its potential to mitigate soil CO₂ emissions. Nevertheless, further researchs are required to understand the underlying mechanisms, environmental determinants, and broader applicability of this approach to mitigate soil CO₂ emissions.

Keywords: agricultural soils, greenhouse gas mitigation, N₂O reductase, pH, liming, inoculation of legumes

Enhanced weathering: from carbon capture to crop production and soil health

Charles Desmalles, AS Developpement, France & Steve McGrath, Rothamsted, UK

Improving the efficiency and environmental impacts of manure based fertilisers through integrated management systems. 

Jihane El Mahdi, Wageningen University & Research, the Netherlands

Animal manures are an important source of nutrients and organic matter, with the potential to replace a large share of synthetic fertilisers, especially in intensive livestock systems. Yet, their current use is unsustainable due to significant losses of nitrogen and phosphorus and emissions of greenhouse gases and ammonia, which contribute to climate change, acidification, and eutrophication. Many technologies have been developed to mitigate these impacts, but they often face the challenge of “pollution swapping,” where reducing one emission increases another. This thesis investigated whether an integrated manure management approach, combining source separation of faeces and urine in dairy housing with complementary treatments, storage options, and field application methods, can overcome this trade-off. Through a series of experimental studies, we found that source separation effectively retains phosphorus in faeces, enables targeted ammonia mitigation, supports efficient anaerobic digestion, and, when combined with adapted field application, can double nitrogen use efficiency while reducing overall environmental impacts without pollution swapping. These results highlight integrated systems starting with source separation as a promising strategy for sustainable nutrient recycling and reduced reliance on synthetic fertilisers.

Agronomic evaluation of multispecies, permanent
pasture, and perennial ryegrass swards managed under grazing

Jane Shackleton, University College Dublin, Ireland 

Reduced reliance on inputs such as fertiliser is fundamental to sustainable grazing systems. As part of the Horizon Europe HEARTLAND+ project, this large two-year grazing study covering 36 hectares compared four sward types: a perennial ryegrass monoculture, permanent pasture, a six-species sward, and a twelve-species sward. Multispecies swards achieved higher herbage dry matter yields than conventional systems despite receiving substantially less fertiliser. Nutritive value was maintained, with multispecies swards showing higher mineral concentrations and lower fibre content. However, herb proportions declined over time, highlighting a management challenge for maintaining sward diversity. These findings demonstrate that multispecies swards can support productive grazing systems while reducing reliance on inorganic fertilisers. The presentation will also place these findings within the broader HEARTLAND+ context, including results related to animal performance and soil responses.

FERTILISER PRODUCTION TOPICS

Strengthening the fertiliser industry with decarbonisation solutions

Stephen Bell, International Fertilizer Association

Fertilisers are a hard-to-abate sector. However, the global fertiliser industry is committed to playing its part in achieving the goals of the Paris Agreement. The industry recognises that an efficient transition to economy-wide, net-zero emissions is the only way to limit global warming. The fertiliser industry’s greenhouse gas emissions span from production to use. Fortunately, there are multiple decarbonisation levers being developed for the fertiliser industry to help reduce some of these emissions while ensuring stable, strong, and sustainable agrifood systems. One of the International Fertilizer Association’s (IFA) central roles is supporting the world’s fertiliser industry to find new ways to meet the dual challenge of feeding the world, and doing it sustainably. This is an exciting and critical moment in which the fertiliser industry is proactively engaged, inspired by the FAO’s 2023 publication Achieving SDG 2 without breaching the 1.5 °C threshold: A global roadmap. This talk will review recent success achieved by the industry, provide an on IFA’s current suite of decarbonisation projects, and highlight some of the remaining challenges and unaddressed opportunities. The talk will focus on technology-based solutions and other approaches being actively explored, from policy and market-based mechanisms to the role of carbon accounting and certification schemes.

Decarbonizing Ammonia: The SKREI project

Geir Thorson Solvi, Yara Clean Ammonia

The SKREI project at Yara Porsgrunn is a pioneering initiative in industrial decarbonization,

integrating green hydrogen produced via water electrolysis into our existing ammonia

production plant. When starting the commissioning process, it was Europe’s largest operational green hydrogen plant.

SKREI leverages proton exchange membrane (PEM) electrolyzer technology to partially replace fossil-based feedstock, significantly reducing CO₂ emissions. The

presentation presents the project’s background, technical approach, commissioning experiences and its strategic role in enabling a low-carbon future for ammonia production.

It also discusses some economic considerations regarding  renewable hydrogen production in Europe.

Phosphogypsum waste or raw material?
The second life of phosphogypsum as a sustainable recyclable material

Dirk Köster, Thyssenkrupp, Germany

Phosphogypsum is a byproduct of the production of Phosphoric acid from natural phosphate rock with mineral acid. This byproduct consists mainly of gypsum (CaSO₄), but also contains impurities such as phosphates, fluorides and sulphates, naturally occurring radio nuclides, heavy metals and other trace elements. More than 80% of this by-product is disposed of without any treatment, usually by dumping in large landfills or even in the sea. The landfills are usually located near phosphoric acid factories, where they occupy large areas and cause serious environmental damage due to the impurities and permitting issues.

Many studies have been carried out in the past on the reuse of Phosphogypsum in various areas, e.g. as a soil stabilizer, low grade fertilizer or as building materials. However, all proposed processes do not solve the problem of Phosphogypsum contamination, and of the huge quantities of Phosphogypsum produced.

Uhde presents now a 2-stage process for the recycling of Phosphogypsum:

1. Phosphogypsum Purification: Cleaning of the Phosphogypsum from contaminants. (P₂O₅ from the Phosphogypsum can be recycled).
2. Purified Phosphogypsum – Conversion into a marketable product: Production of Cement, Ammonium Sulfate or other marketable products from purified Phosphogypsum.

This process enables the conversion of phosphogypsum from waste to a sustainable material by removing impurities and production of a marketable products.

Increasing the range of usable phosphate sources with alternative processes – low-grade phosphates for high value products

Damien Hueber, Technophos

The phosphate world reserves are finite and non-renewable. The quantity and quality of phosphate ores which can be efficiently processed by the traditional technologies are continuously decreasing.

Furthermore, the phosphate mines exploitation is often the source of environmental issues due to the beneficiation process of the mined ores, to reach the required ore quality. This beneficiation necessitates large water quantities and mostly takes place in dry areas where water is a limited resource.

 Technophos, a Bulgarian R&D and innovation facility, is redefining the phosphate industry’s future. The company is specialized in process validation from laboratory to semi-industrial scale and alternative process development, mainly in the phosphate area. Technophos objective is to create value from low-grade raw materials, which are more accessible, necessitate less transformations, create less waste and are overall more sustainable.

Examples of these validated processes are the alternative and advanced EcoPhos (HCl based) and PELP (H₃PO₄ based) processes, proprietary of the Prayon group. Technophos validated and demonstrated, via these processes, the transformation of low-grade ores (down to 12% P₂O₅ content) and secondary phosphate sources (beneficiation tailings, fly ashes, …) into high-value products such as feed-grade DCP and high-purity phosphoric acid. These technologies tolerate impurities, valorize by-products, contribute to circular economy, and achieve recovery rates up to 95%, proving that sustainability and profitability can coexist.

The presentation of this topic will focus on the main characteristics and advantages of the Ecophos and PELP processes.

Advancing nitrogen use efficiency by utilising nitrogen stabilisers in fertilisers

Maarten Staal, BASF, Germany

A Novel Urease Inhibitor to Improve Nitrogen Use Efficiency and Increase Crop Productivity

Ryan Bond, Koch Industries, USA

Agriculture sits at the front line of environmental stewardship and food security, tasked with producing more while safeguarding soils, water, and air. Achieving that balance requires future-forward nutrient strategies and reliable technologies that maintain productivity as conditions grow more variable. Improving nitrogen use efficiency (NUE) remains one of the highest impact levers: by curbing ammonia volatilisation, nitrate leaching, and nitrous oxide emissions, growers can increase crop uptake, protect profitability, and reduce environmental footprints. Nitrogen stabilisers—particularly urease inhibitors (UI)—are proven instruments to improve NUE. Yet many widely used legacy UI actives exhibit performance and application constraints, including sensitivity to soil pH and temperature, incompatibility with acidic fertiliser blends, storage instability, and handling issues that undermine consistency in the field. To address these limitations, Koch Agronomic Services has developed a novel urease inhibitor (technology brand name Duromide). This presentation will highlight its chemistry, summarize key laboratory and field performance data, and discuss strategies for incorporating this technology into future-ready nitrogen management programs.

Friday 12^th December 2025

On Friday there will be two presentations for delegates interested in crop nutrition, two for those interested in fertiliser production. After coffee there will be a new session, with some “quick-fire” presentations from poster presenters, followed by the presentation form the Francis New medal recipient.   

CROP NUTRITION TOPICS

NUTRI-CHECK NET’s 3 step checking approach to nutrition management

Sarah Kendall, ADAS Sustainable Agricultural systems, UK

Despite crop nutrition management requiring urgent transformation to reduce costs and pollution as well as to secure food production, farmers are not well equipped to ‘check’ their crops’ nutritional performance. In fact, on-farm nutrition decisions commonly suffer from guesswork, inaccuracies, imprecision, highly inadequate checking, and thus absent or slow learning, and little progress. The Horizon Europe and UKRI funded project NUTRI-CHECK NET has established a multi-actor, Thematic Network to build farm-level adoption of best field-specific nutrient management practices across Europe. NUTRI-CHECK NET has developed a 3 step checking approach to Nutrition Management of (1) Plan; (2) Check and adjust and (3) Review and has co-created Best Practices associated with each step.

Across nine European countries, the project has collated information about recommendation systems for Nitrogen (N), Phosphorus (P) and Potassium (K), to support Step 1. The project partners have cataloged tools and services available to farmers and advisors to facilitate Step 2 (monitoring and improving their decision-making), which are now available through a custom-built platform and the project’s 26 Crop Nutrition Clubs (which consist of farmers and advisors) have assessed these and used harvest analysis to gauge the value of Step 3. An extensive stakeholder survey highlighted that the main challenges and barriers to adopting tools and technologies were lack of awareness by farmers, lack of education and skills and the high cost of the tools and low-income levels on farms that limits investment. Evaluations of protocols and tools by farmers and experts have addressed their ease of use, trustworthiness, costs, and benefits through a formal Cost Benefit Analysis exercise. The results indicated that economic viability varies depending on the specific tool, crop type, and regional context, emphasizing the need for tailored investment decisions. This study’s synthesis of quantitative economic indicators and qualitative user perceptions highlights that foundational planning tools and those focused on soil consistently deliver the most robust economic returns.

Widespread adoption of the ‘3 Step Checking Approach’ to crop nutrition should enhance nutrient recycling and crop productivity, whilst optimising synthetic fertiliser use and reducing nutrient losses across Europe.

Encouraging improved soil management in Northern Ireland – the Soil Nutrient Health Scheme

Rachel Cassidy, AFBINI, N Ireland

The Soil Nutrient Health Scheme (SNHS) is a national-scale soil sampling and analysis programme designed to enhance nutrient management, carbon assessment, and environmental resilience across Northern Ireland’s agricultural sector. Running from 2022 to 2026, the Scheme is managed by the Agri-Food and Biosciences Institute (AFBI) and funded by the Department of Agriculture, Environment and Rural Affairs (DAERA) through a £45 million investment.

It is open to all farm businesses in Northern Ireland, with over 90% of farms participating to date. Each enrolled farm undergoes comprehensive testing of all fields, generating detailed data on soil nutrient concentrations and pH status, alongside crop-specific fertiliser recommendations tailored to the year of application. In addition, LiDAR-derived runoff risk maps are provided, identifying sub-field areas with elevated potential for nutrient loss to adjacent waterbodies. Estimates of carbon stocks in soils and above-ground biomass are currently in development, with delivery anticipated from autumn 2025. All outputs are made available to farmers via a secure, farm-specific online mapping viewer. Participation in the Scheme also requires completion of training in soil nutrient interpretation and nutrient planning, delivered by the College of Agriculture, Food and Rural Enterprise (CAFRE).

Since its inception, the Scheme has sampled over 450,000 fields and is now entering its final year. This presentation will summarise the key findings to date, discuss implementation challenges, and explore future opportunities for improving soil health, agricultural sustainability, and environmental stewardship at a regional scale.

TECHNICAL TOPICS

Prilling suspensions: Determining the Influence of Particle Size and Solid Content on Jet Breakup and Droplet Formation

Toon Nieboer, Dr Kilian Schnoor, Dr Yavuz Emre Kamis, Vasileios Champilomatis – Kreber BV, Vlaardingen, Netherlands

Prilling, the process of forming droplets from molten materials and solidifying them, is increasingly used for producing multi-nutrient fertilisers from suspension feedstocks. When working with suspensions, which are molten substances mixed with solid particles, the behaviour during jetting and droplet formation becomes complex. Although suspension flow is generally well understood, limited research has been conducted on jet breakup and droplet formation, especially for droplets larger than 500 micrometres yielding an unpredictable prilling process, resulting in varying product properties. 

This study introduces a flexible suspension prilling method applicable for a wide arrange suspensions and slurries and presents a predictive model on droplet formation based on particle size distribution and solid content. Experiments in droplet formation within prilling applications were conducted using suspension with particle sizes below 200 micrometres and different solid contents up to 50 percent by weight. The flow behaviour was analysed under different shear rates, and sedimentation characteristics were observed. Larger particles were found to sediment more rapidly and increase viscosity due to interparticle friction. In contrast, smaller particles exhibited shear-thinning behaviour. 

These rheological findings were used to model jet formation, breakup and droplet generation. Validation was performed using a custom jetting setup combined with dynamic image analysis. Key parameters such as jet breakup length, droplet size and shape, and jetting periodicity were measured. This enabled refinement of the model to predict the entire prilling process based on physical material properties. 

The results show that particle size and solid content significantly affect the non-Newtonian behaviour of suspension. Further incremental improvements will enhance the model’s accuracy. Ideally, dynamic image analysis could be used to estimate the rheological properties of materials that are difficult to characterise due to high melting points or high vapour pressure.

As a follow-up to the rheological study prill samples were produced from various fertiliser mixtures in both pilot and laboratory facilities. These included nitrogen-based fertilisers such as urea and ammonium nitrate, combined with elemental sulphur, ammonium sulphate, potassium sulphate, calcium sulphate and potassium chloride among others. The addition of solids to the melt stream allowed for larger prill sizes using existing equipment. Improvements in product properties were also observed, including increased crushing strength, reduced caking tendency and lower dust formation after handling. 

Natural wetlands for water treatment in fertiliser plants

Matthias de Cazes, Yara International, Porsgrunn/Norway

JOINT PRESENTATIONS

“Quick-fire” poster round

Poster presenters will be invited to give a very short, 2-slide maximum, presentation of their poster to the delegate audience. A challenge to get your message across clearly but briefly. Do you try to say everything, or “leave them wanting more”?! 

Francis New medal presentation:

Feeding the population of the Valeriepieris circle – challenges and opportunities for modern fertiliser production

Harri Kiiski, Brunei Fertiliser Industries, Brunei Darussalam

The Valeriepieris circle is a hypothetical area, comprising the smallest circle that can be drawn which contains 50% of the world’s population. It includes around 10% of the earth’s area. Centred from a city in Myanmar, it spans a region where approximately 90% of the global rice output is cultivated; contributing around 1% of the global greenhouse gas emissions. Rice is deeply ingrained into the cultures of the countries within the circle.

Consuming around 16% of the world’s nitrogen (N) fertiliser, rice production is estimated to lose 25-50% of the N applied to the atmosphere. Rice is both a victim and a contributor to climate change: rising temperatures, droughts and floods threaten yields; cultivation practices accelerate global warming, creating a feedback loop that endangers food security.

Climate impacts are compounded by other issues. Rice production is projected to grow by 30% by 2050. Zinc deficiency so commonplace in south-east Asia, with up to 70% of the population affected, most notably women and children. In addition, unsustainable practices result in land degradation and diminishing soil health.

Creating a new fertiliser plant in a country with no previous fertiliser manufacturing experience is clearly a challenge, but also offers opportunities to seek to address issues both global and local. Considerations of environmental efficiency, high safety standards, biosecurity of transportation and nutrient content were vital in the plant design.