Farming rules for water: new guidance on manure applications

Thursday, 31 March 2022

The requirements for organic manure use on grassland and tillage land under the farming rules for water have been clarified by new statutory guidance. Nicola Dunn, an AHDB environment scientist, highlights the key points.

Applying the farming rules for water (government guidance)

Issued by Defra yesterday (30 March 2022), the new guidance provides the Environment Agency with criteria to help it assess if an enforcement action is required under the farming rules for water. The guidance includes clarifications associated with the autumn spreading of organic materials.

What are the requirements?

  • Applications must be planned. For example, they should follow a nutrient management plan that accounts for crop nutrient requirements, soil sampling and analysis, and nutrients provided by organic manures and manufactured fertilisers

Use the AHDB Nutrient Management Guide (RB209) to assess crop requirements

  • Crop and soil need for nitrogen is to be considered on an annual basis and nitrogen applications should not be applied above the soil and crop needs over an annual cycle
  • Soil phosphorus (P) should be managed to avoid raising the soil P index above the target soil P index over a rotation, unless it is not reasonably practicable and reasonable precautions have been taken to avoid causing pollution
  • Low readily available nitrogen (RAN) organic manures, such as farmyard manure and composts, pose a low risk of nitrate leaching, if reasonable precautions are taken to mitigate the risk of causing diffuse pollution
  • High RAN organic manures (RAN content above 30%) – such as slurries, poultry manures and digestates – are subject to application rate restrictions over the time periods set out below

Soil type


Tillage land

Sandy or shallow soil

1 September to the end of February

1 August to the end of February

All other soils

15 October to the end of February

1 October to the end of February

  • Unless the application is made to meet the soil and crop need for an autumn/winter commercial crop (not cover crop or green manures), the application limit is set to 30m³/ha for high RAN organic manures and 8t/ha for high RAN poultry manures, with no repeat applications within 21 days
  • NVZ closed period restrictions continue to apply in NVZ areas and restrict applications during these time periods
  • Reasonable precautions must be taken, in all cases, to mitigate the risk of causing pollution
  • Reasonable precautions include a requirement to have planned to have established green cover by 15 October (either a commercial crop, cover crop or green manure) unless justified agronomically – for example, due to delayed drilling to control persistent weeds, or to weather medium and heavy soils before a spring root crop
  • Organic manures should also be incorporated into soils within 12 hours as a reasonable precaution, unless it would not be appropriate – for example, where there is a growing crop, it is not practical and risk factors have been assessed, or if precision application methods are being used

Applying the farming rules for water (government guidance)