Closed periods are the times of year when farmers in NVZs are not permitted to spread organic manures with high readily available nitrogen or manufactured nitrogen fertilisers.
To check whether you are farming in an NVZ, visit the Environment Agency's NVZs (nitrate vulnerable zones) map and search for your location.
Farmers in NVZs must not spread high readily available nitrogen manures on or between the following dates.
- Shallow or sandy soils – 1 September to 31 December
- All other soils – 15 October to 31 January
On tillage land
- Sandy or shallow soils – 1 August to 31 December
- All other soils – 1 October to 31 January
What are high readily available nitrogen manures?
High readily available nitrogen manures are those with more than 30% of their total nitrogen content immediately available to crops.
They include poultry manure (layer manure and litter) and liquid organic manures (such as sludge, cattle, and pig slurries and anaerobic digestate).
Manufactured nitrogen fertilisers
Farmers in NVZs must not spread manufactured nitrogen fertiliser on or between the following dates:
- On grassland – from 15 September to 15 January
- On tillage land – from 1 September to 15 January
There are exceptions to the closed periods for both manures and fertilisers.
Please check the relevant guidance at the Gov.uk website: Gov.uk | Using nitrogen fertilisers in nitrate vulnerable zones