NVZ rules and record keeping
Guide

NVZ rules and record keeping

What you must record in an NVZ, when the closed periods fall, the crop caveats that let you spread inside them, and how England, Wales and Scotland differ.

Where the rules apply, and when you can spread

Do the rules apply to you?

That depends on where you farm, and the three countries work differently.

  • England - around 55% of the country is designated as a Nitrate Vulnerable Zone. The rules apply to land inside a zone.
  • Wales - the whole country is covered. The Water Resources (Control of Agricultural Pollution) (Wales) Regulations 2021 replaced the old zone system, so there's no designation to check.
  • Scotland - designated NVZs only, like England.

Interactive map of the Nitrate Vulnerable Zones

Wherever you are, the rules control three things: when you can spread nitrogen, how much you can apply, and what you have to write down. The detail below is England unless stated, and the country differences are set out further down.

Closed periods

There are two sets, one for organic manures with high readily available nitrogen (slurry, poultry manure, liquid digestate) and one for manufactured nitrogen fertiliser.

Chart of NVZ closed periods from August to February, showing the four organic manure windows and two manufactured nitrogen windows, with the Wales and Scotland differences noted underneath

Organic manures with high readily available N:

  • Grassland on sandy or shallow soils - 1 September to 31 December
  • Grassland on all other soils - 15 October to 31 January
  • Tillage land on sandy or shallow soils - 1 August to 31 December
  • Tillage land on all other soils - 1 October to 31 January

There's a useful exception on sandy or shallow tillage land: if a crop is sown on or before 15 September, you can still spread between 1 August and 15 September.

Manufactured nitrogen fertiliser:

  • Grassland - 15 September to 15 January
  • Tillage land - 1 September to 15 January

Farmyard manure and other low readily available nitrogen materials aren't caught by the closed period in the same way, but they're still caught by the limits and by the general rules on soil condition.

The crops you can still fertilise in the closed period

The manufactured nitrogen closed period isn't absolute. Specific crops have allowances, and they're capped:

  • Winter oilseed rape - up to 30kg N/ha, and nothing after 31 October.
  • Grass - up to 80kg N/ha, no more than 40kg N/ha in any one application, and nothing after 31 October.
  • Brassicas - up to 100kg N/ha, and no more than 50kg N/ha in any four week period.
  • Asparagus - up to 50kg N/ha.
  • Salad onions, bulb onions and parsley - up to 40kg N/ha.

How much you can apply, and where

The three limits

Three separate ceilings, and it's possible to satisfy one while breaching another.

  • The farm limit. 170kg of total nitrogen per hectare per year from livestock manure, averaged across the holding. Grassland farms can apply for a derogation taking this to 250kg.
  • The field limit. 250kg of total nitrogen per hectare from all organic manures in any 12 month period, on any single hectare. Manure dropped by grazing animals doesn't count towards it.
  • N max. A crop-by-crop ceiling on total nitrogen, counting crop-available nitrogen from organic manure as well as the bag. Working out the crop requirement it's measured against is an RB209 job.
After the closed period

This one gets missed a lot. From the end of the closed period until the end of February you can't apply more than 30m³/ha of slurry or 8 tonnes/ha of poultry manure in a single application, and you must leave at least three weeks between applications.

Where and when you can spread
  • Not within 10 metres of surface water, reduced to 6 metres if you're using precision equipment such as a low trajectory band spreader.
  • Not within 50 metres of a spring, well or borehole.
  • Not when the soil is waterlogged, flooded, snow covered, or has been frozen for more than 12 hours.
  • Not on steeply sloping land where there's a significant risk of run-off.

These sit on top of the Farming Rules for Water, which apply to every farm in England whether or not it's in an NVZ. Where the two regimes give different distances, work to the tighter one.

Records, country differences, and where inspections go wrong

The records

You can't fix records on the day of a visit. Keep all of the following for at least five years:

  • A risk map showing watercourses, springs, wells and boreholes, soil types, slopes, drains, and any land you can't spread on.
  • Your field records, updated within a week of sowing, fertilising or harvesting.
  • Your nitrogen calculations - soil nitrogen supply, crop requirement and the N max position.
  • Your manure records - type, quantity, date, spreading method and nitrogen content, including anything imported or exported.
  • Your livestock numbers, with days on the holding and the nitrogen produced, by 30 April each year.
  • Evidence of storage capacity. Our manure and slurry storage guide covers how that figure is worked out and what has to go into it.

The soil analysis those calculations rest on needs to be current too - see the soil sampling guide for how often and what to test for.

How Wales differs

The whole country is covered rather than designated zones. Beyond that there is one closed period difference: organic manure on grassland on non-sandy soils ends 15 January in Wales, 31 January in England.

Everything else lines up. The manufactured fertiliser closed periods, the post-closed-period restrictions and the 170kg and 250kg limits are the same. The livestock standard values and manure analysis values differed under the original 2021 regulations, but a 2022 amendment brought them back into line with England.

How Scotland differs

Rules apply inside designated NVZs, as in England. For organic manures the closed periods are effectively identical, with one extra allowance: on sandy or shallow tillage land Scotland also lets you spread up to 30 September where oilseed rape, a catch crop or a cover crop is sown by then.

The real difference is manufactured nitrogen, where Scotland's closed period runs about a month longer:

  • Most Scottish NVZs - grassland 15 September to 15 February, tillage 1 September to 15 February.
  • The Moray, Aberdeenshire and Banff & Buchan NVZ - both run to 20 February.

Scotland also restricts organic manure quantities in two windows, the four weeks before the closed period as well as after it until 14 February, where England only restricts afterwards. And Scotland's statutory list of manures omits a few materials England includes, such as horse and goat farmyard manure and separated slurry solid fractions.

Where inspections go wrong
  • Planning after the fact. The rules expect the nitrogen to have been planned before it went on. Records reconstructed from delivery notes in December are obvious to an inspector. A plan built in Soil Benchmark carries the date it was made, so the sequence speaks for itself.
  • Manure counted in tonnes, not nitrogen. N max is a nitrogen ceiling, so the record needs a kilogram of nitrogen figure. Thirty tonnes of muck doesn't answer the question.
  • Averages that hide a field. Meeting 170kg/ha across the holding is no defence if one field took 300kg.

Sources

Last checked 28th August 2026. Rules change - check the source before relying on a figure.

Building a nutrient management plan

RB209 recommendations, with the manures counted properly

Nutrient Nerd builds the RB209 plan for arable and grassland, counts organic manures as available N, P, K and S rather than tonnes, and checks closed periods, N max and field limits as you plan rather than afterwards. It produces linked job sheets for whoever's spreading, and a compliance certificate you can show inspectors or the supply chain.
See Nutrient Nerd

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