Farming in a Nitrate Vulnerable Zone – What are the rules and how can you stay compliant?

Farming in a Nitrate Vulnerable Zone – What are the rules and how can you stay compliant?

Nitrate Vulnerable Zones (NVZs) are areas designated as being at risk from agricultural nitrate pollution. When you are farming on an NVZ there’s a limit on the amount of manufactured fertiliser and crop-available nitrogen from organic manure that you can apply to most crops each year. In England they include about 55% of land (Source), you can find out if your land is in an NVZ using this interactive NVZ map.  

Failure to follow NVZ rules can lead to reductions in payments of BPS, Countryside Stewardship and Countryside Productivity schemes. The RPA carries out checks as part of its cross compliance inspections. We have put together a checklist of the key record-keeping requirements when farming in an NVZ and ideas for how you can use fieldmargin to follow them and keep your records organised for inspections. You can find full up-to-date guidance on the DEFRA website here

Key record-keeping requirements in an NVZ

  • The size of your farm
  • A risk map
  • Field records for crop sowing, spreading organic manure or manufactured fertiliser, yields of arable crops
  • The number of livestock kept on your farm for the year and a calculation of the nitrogen produced by them
  • Records of storage of manure, silage and slurries
  • Records showing calculations of available nitrogen

Producing an NVZ risk map of your farm

If you spread organic manure on your farm you have to have an up to date risk map which shows areas where there is a high risk of nitrogen run off. Here is how to make a risk map on fieldmargin using our mapping tools and map uploader.

  1. Show each field and its area in hectares – you can map your fields by following our instructions here. Their areas will automatically be calculated.
  2. Upload any existing maps you have – you can upload maps that you have on paper and scanned or as pdf and they will be added as a map layer so that you don’t have to draw the information again. This is particularly useful for drainage maps.
  3. Add detail using features: you must map the following:
  • Areas with sandy or shallow soils 
  • Land with a slope greater than 12 degrees 
  • Land drains (except if they are sealed and impermeable) 
  • Sites suitable for temporary field heaps (if you intend to use them to store manure) 
  • Land that has a low run-off risk (if you intend to use it for spreading during the storage period to reduce your storage capacity requirement) 
  • All surface waters on your holding and land within 10 metres of them 
  • All springs, wells and boreholes on your holding, and within 50 metres of the boundary of your holding, and land within 50 metres of them.

You can turn off features that you don’t need to refer to frequently using the layers panel so that the map doesn’t appear too cluttered.

Planning and recording nitrogen applications

You must have records of the following field operations, which can all be recorded using Field Jobs (see below for more information on how):

  • Sowing
  • Organic manure
  • Manufactured fertilizer
  • Crop yield

You should also keep records of any tests or other methods used to assess soil N supply (these could be recorded with a monitoring site), crop N requirements and advice from a FACTS qualified adviser. These can all be added as notes attached to fields (any files such as pdfs can be uploaded) meaning that this information can easily be found when needed.


For crops where you plan to spread nitrogen fertilizer you are required to record the type of crop and the date of sowing. This can be done using a Field Job as in the example below. If you set up your sowing jobs in advance you can easily record when they were done by tapping ‘Mark as Complete’, if you forget or are putting in records after the operation was completed you can edit the completion date. You can also set the field usage which makes it easy to see on the farm map which crops were being grown where for a given farm year so you have an easy way of checking current and previous crops.

Organic manure spreading

When spreading organic manure you should record:

The area spread As you attach fields to a Field Job their area is added to the Job, you can amend these for greater accuracy by altering the Work Area.

The type of manure and quantity spread You can set up different organic manures that you use as inputs. You can give inputs whatever name you want so you could even include the nitrogen content (e.g. ‘Slurry – X% N). When you add an input to a Field Job you set the rate it was applied at or the total that was used for the whole job.

The planned and actual date of spreading You can set up a due date to indicate when you plan to apply your manure. This can be amended if you have to change your plans, for example due to wet weather. When you mark a Job as complete the completion date is automatically recorded. You can edit this date if you are recording work after it has been done.

The method of spreading This can be put in the job title or a as a comment

The total N content and amount of nitrogen that was available to the crop These can be recorded as comments on the Field Job

Manufactured fertilizer spreading

When spreading manufactured fertilizer you should record:

The date of spreading  When you mark a Job as complete the completion date is automatically recorded. You can edit this date if you are recording work after it has been done.

The amount of nitrogen spread You can set up the fertilizer you are using as an input name, including the N%, so it is simple to check the amount of Nitrogen applied later on. For example ‘Urea 46%’ or ‘Ammonium Nitrate 27%’. You can set the amount applied when you add the input to a Field Job as a rate or the total used in the application.

Crop yield

For arable crops you should record the yield harvested to show that this is in line with your estimated yield used to calculate N-max levels. You can do this by creating a Field Job with type ‘Harvesting’ and then you can record what you harvested as an input. Find step-by step instructions here.

Checking you are within your N-max limit

You can check the amount of fertilizer, manure or any input that has been applied to a field by opening the field and going to the ‘Inputs’ tab. This will show you the total quantity applied and the rate/ha so you can easily calculate how much more nitrogen can be applied to the field for that year.

Checking upcoming and completed work

Select the to-do list to see upcoming applications and select history to view key dates of Nitrogen applications. The history view is particularly helpful to show a chronology of when work was done in the field so that you can show that no applications have been made during the closed period. 

The 2020 NVZ closed period dates (when you can’t spread high readily-available nitrogen fertilizers such as manure, slurry or inorganic fertilizers) are:

1 September – 31 December on sandy or shallow soils, 15 October – 31 January on all other soils

Tillage land
1 August – 31 December on sandy or shallow soils, 1 October – 31 January on all other soils

Inputs and reports are part of fieldmargin Pro. See how it could help on your farm with a free 14-day trial of Pro. No credit card required.

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