Industry self-regulation of the use of uninhibited urea fertilisers

For nearly two years, an industry consortium that has included the AICC and NIAB has worked together and with Defra to establish a viable alternative to the proposed ban on the sale of uninhibited urea fertilisers. Widely reported as Option 4, it involves an industry-led approach to promoting and encouraging best practice for substantially reducing ammonia emissions from agriculture by 2030, particularly from the use of urea and liquid UAN fertilisers. It includes mandating the use of urease inhibitors with urea and UAN fertilisers, at certain times of the year, with compliance assessed through the Red Tractor assurance schemes.

The ability to use uninhibited urea saves farmers £13.8 million annually. And its value stretches further when you consider its role in keeping UK agriculture competitive and minimising potential nutrient leaching risks associated with early season use of ammonium nitrate fertilisers.

With the Government’s Clean Air strategy targeting, amongst other things, a reduction in ammonia emissions, the farming industry must demonstrate that it can play its part, while maintaining competitiveness. Responsible use of urea fertilisers will demonstrate that there are effective alternatives to government regulation, and open the door to other industry-led solutions.

The consortium has written to Defra, in response to a letter last week from Defra to the consortium, to formally propose a way forward that broadly meets the wishes of all parties involved. This proposal has yet to be accepted by Defra but, to provide much needed clarity to farmers and agronomists, we can say:

1. The use of urease inhibitors with solid urea and liquid UAN fertilisers between 1st April and 14th January each year is very likely to be mandatory and enforceable from 1st April 2024. So farmers should be aware of this when ordering nitrogen requirement for the 23/24 cropping season.
2. After the 1st April 2024, it is expected, but not yet certain, that the use of uninhibited urea or UAN will ONLY be allowed between the 15th January and the 31st March each year. Of course, if weather or soil conditions are conducive to ammonia emissions, farmers and agronomists should consider delaying application until conditions improve (but still within the above period), using inhibited urea or UAN if feasible, or alternatively using ammonium nitrate instead.

This 10-week period up to the end of March is a critical time for nitrogen fertiliser use and a significant volume is applied to arable crops and grassland, particularly from mid-February. As a result, we would hope that fertiliser suppliers will account for this and allow farmers the ability to purchase both inhibited and uninhibited solid urea, if they wish to do so. Inhibitors for liquid fertiliser are purchased separately and added to the spray tank at time of application.

Although, the focus of Option 4 has been on the use of urease inhibitors, they are not a silver bullet for reducing emissions. They are only partially effective, and products may vary in their efficacy under different conditions. Please consult your AICC or NIAB agronomist for more information.

We would also recommend the following best practice guidelines for all urea and UAN fertiliser use:

1. If broadcast, apply urea and UAN when the soil surface is wet or if significant rainfall is expected imminently (whilst, of course, accounting for possible runoff and soil erosion);
2. Don’t apply urea or UAN, particularly if uninhibited, to moisture-limited or rapidly-drying soils;
3. Incorporate urea and UAN fertilisers into the soil if practically and agronomically possible;
4. Consider, if possible, the use of ammonium nitrate fertilisers as an alternative, particularly in moisture-limited soils, and in April and May when it is drier and warmer;
5. Application to bare soil is likely to be a higher risk than applying to an established crop. For example, application to a spring barley seed bed, in drying conditions, is likely to be a higher risk than to winter wheat in April although care still needs to be taken in both situations;
6. Sandy soils, and shallow soils over chalk or limestone, are at higher risk than high clay or organic soils but, again, care is encouraged for all soil types.

The consortium have put together a short BASIS Classroom course around the subject of reducing ammonia emissions, which was launched on the 27th March.

BASIS module: How to Reduce Ammonia Emissions from Farming

This is free to FACTS Qualified Advisors and up to 500 non-members.

NIAB and the AICC hope this statement provides clarity to our farmer and agronomist members and their clients.