As we move further into 2025, farmers in England need to ensure they are fully compliant with the urea fertiliser rules that came into effect on 1st April 2024. These rules, now embedded within Red Tractor standards, are part of a voluntary industry-led approach designed to reduce ammonia emissions – and prevent a total ban on untreated urea.
Why were the rules introduced?
The UK Government is legally obligated to reduce ammonia emissions, a significant proportion of which comes from agriculture, particularly through fertiliser use. Initially, the Government proposed a ban on untreated urea fertiliser. However, following consultation with the farming industry, a voluntary alternative was agreed: the Option 4 self-regulation scheme.
Under Option 4, the farming industry committed to changing its approach to urea use in return for avoiding strict regulations or a blanket ban. This agreement was adopted into the Red Tractor assurance scheme and became a mandatory standard from April 2024.
What are the rules?
The key requirement is that, from 1st April 2024, fertiliser containing more than 1% urea must either be treated with a urease inhibitor or applied only within the permitted time window (15th January to 31st March).
This requirement is part of the Clean Air Strategy, which recognises protected urea as a key measure for reducing ammonia emissions from agriculture.
Treated (inhibited) urea – permitted use year-round
- Solid urea must be treated with a urease inhibitor and used within its use-by or best-before date.
- Liquid urea must include an inhibitor applied at the prescribed rate, also within its valid use period.
With these protections in place, inhibited fertiliser can be used year-round while meeting environmental targets.
Fertiliser inhibitors
There are two main types of fertiliser inhibitors that support compliance and reduce nitrogen loss:
1. Urease inhibitors
These block the activity of the urease enzyme, slowing the conversion of urea to ammonia, which reduces volatilisation losses and emissions. These are required for most urea-based fertilisers used after 1st April.
2. Nitrification inhibitors
These target soil bacteria responsible for converting ammonium to nitrate and nitrite to nitrate, helping to reduce nitrate leaching and nitrous oxide emissions.
Both types are essential tools for improving nutrient use efficiency and limiting environmental impact – particularly when using urea in conditions that favour volatilisation.
Untreated urea – limited use in England
If you are using untreated (unprotected/uninhibited) urea, you must follow strict timing rules:
Solid untreated urea:
- Can only be applied between 15th January and 31st March.
Liquid untreated urea:
- Can also be applied between 15th January and 31st March.
- After 1st April, it is only permitted with agronomic justification by a FACTS-qualified adviser or suitably trained farm staff listed on the FACTS Professional Register.
What qualifies as agronomic justification?
Red Tractor recognises a few specific cases where untreated liquid urea may be used after 1st April:
- Incorporation into the soil by injection, or within 48 hours using irrigation or cultivation.
- Use in foliar applications where fertiliser is sprayed using ag-chem nozzles, following manufacturer guidance.
Other factors like soil type, crop canopy, and surface moisture may be taken into account by qualified advisers, but these are considered less reliable at reducing emissions. In many cases, using an appropriate inhibitor remains the most effective route for compliance and environmental protection.
How is compliance being monitored?
Uptake of the rules is being tracked through:
- Fertiliser sales and treatment data
- Red Tractor audit inspections
- The British Survey of Fertiliser Practice
These measures help demonstrate that the industry is meeting its responsibilities under the Clean Air Strategy and the Option 4 self-regulation agreement. If compliance fails, stricter regulations may be reintroduced in the future.
What about the rest of the UK?
The urea rules outlined here apply specifically to England, under the Red Tractor scheme and the terms of the voluntary Option 4 agreement. In Wales, Scotland, and Northern Ireland, fertiliser containing urea (solid and liquid) can be applied as per the relevant legislation.
What happens if you don’t comply?
If you are found to be non-compliant with the new standard, you may be required to complete a BASIS training module: Reducing Ammonia Emissions
This module, created in partnership with industry bodies such as AIC, AICC, CLA, NIAB, Red Tractor, and the NFU, equips farmers with practical knowledge for reducing emissions across fertiliser use, organic materials, and housing systems.
Stay compliant & reduce your risk
Meeting the new rules on urea use is essential for all farming businesses. While urea fertilisers remain a key part of nutrient management, ensuring you’re using them correctly is now more important than ever. Understanding and following the current requirements will help you stay compliant, protect your Red Tractor status, and support the industry’s wider environmental goals.
Further information
Farmers are being encouraged to take part in the BASIS module: How to Reduce Ammonia Emissions from Farming which has been developed with the industry.
Help & advice
For further advice and support, please contact CXCS on 01981 590 514 and speak to a member of our Agricultural Compliance or Farm Assurance team.