New project set to predict nutrient release from cover crops

How to account for nutrients in cover crops is the subject of a new desk study funded by AHDB Cereals & Oilseeds and three water companies (Anglian Water, Southern Water and Wessex Water).

The four-month, ADAS-led project will include assessments of decision support tools that estimate the quantity of nitrogen and nutrient release patterns associated with a wide range of cover crop species.

An online questionnaire and a stakeholder workshop will canvass opinions on the project and identify the resources needed to improve nutrient management planning across rotations.

Joanna McBurnie, AHDB Environment Scientist, said:

“Payment incentives and the movement towards the adoption of regenerative agriculture, which advocates keeping the soil covered, have accelerated the adoption of cover crops on UK farms.

“Some benefits of cover crops are clear, such as reducing soil erosion and nitrate leaching risks. One of the biggest knowledge gaps is associated with legacy effects.

"This project will provide evidence on the amount and timing of nutrient release from cover crop residues.”

The development of reliable information on nutrient release is complicated by the:

• Availability of a wide range of cover crop species (including mixes)
• Diversity of agroclimatic conditions across the country (e.g. soil types, cropping and weather)
• Differences in management practices (e.g. sowing and destruction dates and methods)

Other countries, notably France and the USA, have already developed decision support tools. These use predictive models to estimate the availability of nitrogen from a wide range of cover crops to the next cash crop. This project will build on such tools.

A short questionnaire, which is open until the end of the month, is gathering views from people who grow or provide advice on cover crops.

The questions capture the ways people account for nutrients from cover crops and assess the potential to develop a decision support tool for the UK.

The work will also consider how nutrient management guidance may need to change. This includes information presented in our Nutrient Management Guide (RB209).

An online stakeholder workshop will also take place on 29 April 2025 to discuss the interim findings and direct the last few weeks of the project, which concludes at the end of May.