MGA joins collaborative project tounlock the potential of legacyphosphorus in maize soils

The Maize Growers Association (MGA) is delighted to be part of an exciting new collaborative project exploring how maize growers could make better use of phosphorus already present in their soils; potentially reducing fertiliser costs while maintaining crop performance and improving environmental outcomes.

The project, “Smart P use in soils with legacy P: Testing biological and chemical phosphate-free alternatives to DAP starter fertiliser in maize,” brings together farmers, researchers, industry specialists and knowledge-exchange organisations to tackle a challenge that will be familiar to many growers: soils which already contain significant reserves of phosphorus, but where much of that phosphorus is unavailable to the growing crop.

Phosphorus is essential for crop establishment and growth, and DAP starter fertiliser has traditionally been used by many maize growers to support early crop vigour. However, phosphorus can become locked up in the soil over time, creating reserves of so-called “legacy P”.

With a significant proportion of UK arable soils already above the target phosphorus index, there is an important question for growers: can we make better use of the phosphorus already in our soils rather than continuing to add more?

That is exactly what this project intends to investigate.

Putting practical solutions to the test

The project will establish replicated strip trials across three commercial maize fields with soil P indices above 3.

Four approaches will be compared: standard farm practice using a full rate of DAP; a no-phosphorus control using urea; urea combined with Phosta, a phosphorus liberator designed to release mineral-bound P; and urea combined with Calfite Extra and Luxor, an approach intended to stimulate rooting, soil biology and the mobilisation and uptake of organic phosphorus.

Importantly, these are practical treatments which can be applied using standard farm machinery. The trials are therefore designed not simply to answer an interesting scientific question, but to generate evidence which maize growers could put into practice on their own farms.

Measurements will look at crop growth throughout the season as well as yield, dry matter, feed quality, phosphorus offtake and return on investment at harvest. Soil health and microbial communities will also be assessed, giving the project an opportunity to understand not only whether the treatments work, but potentially why they work.

Collaboration at the heart of the project

For the MGA, one of the most exciting aspects of the project is the breadth of experience around the table.

The consortium brings together the Maize Growers Association, Vulcan Renewables, Future Biogas, J & J Burnett, Oakbank Game & Conservation and Rothamsted Research, alongside input from the businesses supplying the products being tested.

Each organisation brings something different to the project – from commercial maize-growing experience and practical field operations to soil science, trial design, laboratory analysis and communication with growers.

That collaborative approach is hugely valuable.

Too often, promising ideas can remain separated between research, commercial agriculture and the businesses developing new technologies. Bringing those groups together around commercial-scale field trials provides an opportunity to combine scientific rigour with the realities of growing maize on farm.

The MGA's role will be particularly important in making sure that growers are part of the conversation.

MGA Technical Lead Jon Myhill and Treasurer Neil Groom will support the project's knowledge-exchange activities, helping communicate progress and, ultimately, ensuring that the findings reach the maize-growing community.

The project team collectively has networks extending to more than 600 farmers, giving the work significant potential to stimulate discussion and encourage adoption if the treatments prove successful.

Learning from growers as well as the trials

Knowledge exchange is being built into the project from the beginning rather than simply being added once the results arrive.

Alongside the field trials, the project will ask farmers about their own experiences of managing high-P soils and the approaches they have tried to improve phosphorus-use efficiency.

This is an aspect of the project that the MGA is particularly excited about. There is a huge amount of practical knowledge within the maize-growing community, and combining growers' experiences with robust replicated trial data should create a much richer picture of what works, where it works and how different approaches might fit within existing farming systems.

The trial fields themselves will also become a focus for knowledge exchange, including an on-farm trials day ahead of harvest so growers can see any differences between treatments first-hand.

Once results are available, findings will be shared through the MGA's grower network, technical briefings and the MGA annual conference, alongside wider industry communications.

Potential benefits for maize growers

If the project demonstrates that legacy soil phosphorus can be successfully mobilised without compromising maize yield or forage quality, the implications could be significant.

The project application estimates that replacing a typical 100kg/ha DAP application with the equivalent nitrogen supplied through urea could save around £49/ha before accounting for the cost of the alternative treatment.

Across the UK's maize area, even relatively modest reductions in unnecessary phosphorus applications could therefore represent a substantial saving for growers.

There are wider benefits too. Making greater use of existing soil P could reduce dependence on imported rock phosphate, help farms manage high soil P indices and potentially lower the risk of phosphorus losses to water.

But crucially, the project is not assuming that an alternative will work simply because the theory is promising. The purpose of the trials is to generate the independent, practical evidence growers need to make informed decisions.

That is where collaboration between farmers, researchers, industry and organisations such as the MGA becomes so valuable.

For the MGA, this project represents exactly the type of practical, farmer-focused research that can help move the maize industry forward: identifying a real challenge on farm, bringing together the right expertise to investigate it properly, and making sure that growers are involved throughout the process.

We look forward to working with all of the project partners, following the trials as they develop and, most importantly, sharing what we learn with MGA members and the wider maize-growing community.