2026 IFS webinar series
A programme of webinars covering a variety of topics relating to fertiliser production and crop nutrition
During 2026 IFS will continue to organise webinars for those involved and interested in the production and application of fertilising products. These webinars will be in the same format as in previous years.
Society Members are able to attend all these webinars without charge, as well as having free access to the presentation charts, a recording of the webinar, and a pdf copy of the written paper, where applicable. For UK attendees, each webinar will be worth BASIS FACTS CPD points.
Non-members are also welcome to attend, for a charge of £25 per webinar, or £35 for a webinar plus access to a pdf of the presentation charts, recording of the webinar and pdf of written papers, where applicable. Selected webinars will be free to all.
Detailed information on the webinars that comprise this programme is shown below. Updates will be added as these are finalised. Webinar registration will open for each webinar as its details are confirmed, and will be accessed from the section for each webinar, below.
aspects of soil compaction
Felipe Bachion de Santa and Guido Bakema
Wednesday 13 May 2026
PRESENTATIONS FROM THE BRIAN CHAMBERS AWARD WINNERS – free to view
Bright Laboan, Wilfred Adjadeh, David Clarke, Lillian Hearn
Tuesday 3 March 2026
Site-specific organo-mineral fertiliser (OMF) for sustainable coca nutrition in West Africa
Bright Laboan, Cranfield University, UK
The West African cocoa belt soils are dominated by low pH and high Al and Fe, which bind phosphorus (P), reducing P availability for cocoa plant uptake. This ultimately results in low cocoa bean yield in the region (300-600 kg/ha), affecting global cocoa demand and farmers’ livelihood. This work investigated whether the use of organo-mineral fertilisers (OMF), created from cocoa pod husk (CPH), cocoa placenta (PL) and poultry manure (PM) with a small quantity of mineral fertiliser, could offer a sustainable nutrient management solution for cocoa production.
The results showed that OMF outperformed mineral fertiliser in terms of increased yield, with the additional benefit that the residual soil fertility was sufficient for a subsequent cropping year without additional fertiliser application. This potentially increases the economic benefit to growers. The use of cocoa waste/poultry manure was able to supply 70-85% of the nutrients required for cocoa production, reducing the mineral fertiliser demand. Further work is needed to assess the on-going residual effects beyond a second cropping year.
Optimising nitrogen fertilisation by balancing crop yield and nitrate leaching trade-off
Wilfred Teejay Adjadeh, Aarhus University, Denmark
Nitrate leaching remains an environmental concern, requiring N management strategies to balance crop productivity and leaching losses. There, has been limited work describing the yield leaching trade-off. Marginal losses differ by soil, crop sequence, N rates, and legacy N, and a better understanding of these differences is needed for regulation and management.
This study assesses marginal leaching at multiple points along the entire yield–leaching curve. It draws on multi-year, real-world field trials from Danish farms, allowing for the investigation of legacy effects. It is based on the concepts of nitrogen fertiliser-use efficiency (NfUE) and N surplus, which link N inputs, crop uptake, and environmental losses. As fertiliser rates and soil N supply exceed crop demand, N surplus rises, NfUE declines, and marginal leaching increases nonlinearly, particularly under repeated cropping with residual soil N accumulation. The results highlight a clear trade-off between maximising yield and minimising N losses, challenging the notion that both can be optimised simultaneously and emphasising the need to balance yield goals with acceptable N losses under regulatory frameworks.
Crop modelling for improved nitrogen management in UK wheat
David Clarke, Niab/Cranfield University, UK
Nitrogen use efficiency (NUE) in UK wheat is, at 60-70%, below the economic and environmentally optimal target of 90%. The economic optimal N rate (NOpt) can vary by 100–200 kg N/ha within fields, highlighting the need for site-specific N management.
This research applies the Sirius crop simulation model to UK wheat at the sub-field scale using real farm data, integrating spatial datasets to simulate soil–crop–weather interactions. This permits simulation of soil variation and environmental risk, allowing specific N management across field zones.
The first step was to validate the model, using high-quality, long-term data. SIRIUS accurately reproduced grain yield, protein, and grain N uptake across soil types, N rates, and years, indicating sufficient performance to support sub-field N management on farm. Using the model in a field setting indicates potential benefits of increased NUE, improved financial margin/ha, increased N recovery and decreased greenhouse gas losses. Use of the model is now being evaluated in on-farm trial work.
The legacy effect of long-term crop rotations on carbon drives differences in nitrogen turnover dynamics
Lillian Hearn, University of Melbourne/Agriculture Victoria, Australia
This work looked at the effects of long-term rotations and carbon dynamics on nitrogen (N) losses through denitrification, using an N15-labelled microcosm method.
Using a long-term trial site with a number of crop rotations, which offered a range of dissolved organic carbon (DOC) contents, measurements were made of nitrification, nitrate consumption and gaseous losses as nitrous oxide (N2O) and dinitrogen (N2) across three rewetting thresholds – aerobic soil (60% water filled pore space (WFPS); partially anaerobic (75% WFPS) and aerobic (90% WFPS).
The degree of rewetting affected which N turnover process dominated. Increased DOC also indicated greater potential denitrification rates. Whilst managing soils for increased carbon is beneficial for soil health, the research suggests that optimisation of NUE requires consideration of soil moisture status as well as actions to preserve carbon status. Improving the synchrony of crop demand and N supply, to limit the soil nitrate supply is also important.
Estimating soil compaction risk using meteorological data and soil spectroscopy
Felipe Bachion de Santa, Teagasc, Ireland
Soil compaction is a major constraint to sustainable agriculture in Europe, affecting crop productivity, carbon sequestration, and greenhouse gas emissions. In this webinar, I will present a methodology that we used to estimate soil compaction risk using existing soil archives (n~10,000 pits) at regional scale (4 km² resolution) by integrating soil spectroscopy, field information and meteorological data.
For topsoils, medium infrared (MIR) spectroscopy was used to predict particle size distribution (sand, silt, clay) and organic matter content. These properties were combined with soil drainage classes to assess susceptibility to compaction.
For subsoils, MIR predictions of particle size and bulk density were combined with climatic indicators of soil wetness to evaluate inherent compaction risk.
This approach demonstrates how the use of existent soil archives combining spectroscopy with environmental data can offer a fast, cost-effective, and scalable alternative to support large-scale soil monitoring and risk assessment.
Soil compaction by increasing wheel loads major threat for soil health
Guido Bakema, Wageningen University & Research, the Netherlands
Soil compaction has been described as one of modern agricultures major problems. Increasing intensification of agriculture and with that, the increasing use of heavy machinery is one of the main contributors to soil compaction. Soil compaction potentially causes a decrease in soil qualities like permeability of water and air, infiltration capacity, water storage, oxygen supply and rootability. This can lead to decreases in crop productivity, economic losses, drought, surface water pollution, and natural disasters. According to the European Commission (2020) the best estimates suggest that between 23 to 33% of European land fails soil health due to soil compaction, of which 7% is outside of agricultural areas. Based on several international studies it was concluded that this soil compaction can result in production losses for farmers between 10 to 40%. Two types of soil compaction can be distinguished: topsoil (down to 25 cm below the surface) and subsoil compaction (between at least 25-50 cm below the surface) In agricultural soils, the arrangement of the pore system often differs between topsoil and subsoil the topsoil can better be described as a sponge-like pore system with random structure due to tillage, while the subsoil is more structured and mainly has vertical (bio)pores that determine air transport. Plants need different resources from both topsoil and subsoil and therefore compaction in any of these layers can result in limited access to resources. However, topsoil compaction can quickly recover with the right management practices, while subsoil compaction is difficult to recover and can even be permanent.
In the presentation the following will be addressed:
- What is topsoil and subsoil compaction? (and why focus on subsoil)
- Major cause of compaction by increasing wheel loads (and why innovations increases the problem)
- The influence on subsoil compaction on soil functions, water bearing capacity and runoff (and how this influence the use of fertilizers)
- Resolving the wicked problem of soil compaction (and why it’s also a social-economic problem)
This webinar has 2 BASIS FACTS CPD points allocated, for UK attendees