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How do NVZs affect farming

What is AN NVZ?

NVZ stands for Nitrate Vulnerable Zones. These are areas seen as being at high risk from agricultural nitrate pollution.  About 55% of all land in England has been designated as Nitrate Vulnerable Zones (NVZs). 

All landowners in these areas must comply with the NVZ rules which are enforced by the Environment Agency.

How NVZ affect farms

If your land is within one of the NVZ, there are rules that you legally have to follow:

  • When you use nitrogen fertiliser.
  • When you store organic manure.

You can find a full set of the rules included in our recently published Manure Applications Guide which can be downloaded below.  The text in brown relates to the NVZ rules specificially. 

Using nitrogen fertiliser – manufactured or organic

Nitrogen fertilisers can be manufactured fertilisers that you purchase, or organic manures that you produce, or bring onto your farm.

There are limits to the average amount of manufactured fertiliser, and nitrogen from organic manure that you can apply to crops each year – the N-max limit.

N-max limit (kilograms of nitrogen per hectare)

Autumn or early Winter-Sown Wheat 220
Spring-Sown Wheat 180
Winter Barley 180
Spring Barley 150
Winter Oilseed Rape 250
Sugar Beet 120
Potatoes 270
Forage Maize 150
Field Beans/Peas 0
Grass 300
Asparagus, Carrots, Radishes, Swedes, individually or in any combination 180
Celery, Courgettes, Dwarf Beans, Lettuce, Onions, Parsnips, Runner Beans, Sweetcorn, Turnips individually or in any combination 280
Beetroot, Brussels Sprouts, Cabbage, Calabrese, Cauliflower, Leeks individually or in any combination 370

All applications of nitrogen on each crop in each field (including grass) must be planned, and this is your fertiliser plan. The plan must be kept as part of the farm records. For help keeping farm records, talk to our farm business consultants.

There are a series of steps that have to be taken before you apply nitrogen; these vary according to whether it is the first time of application or following growing seasons.

Livestock manure, and any organic manure have to be treated in a different way with the total and crop-available nitrogen levels needing to be calculated before application.

Run-off risk

Whenever nitrogen fertilisers are used, it is essential that an assessment be made of the risk of run-off.

  • Land that’s sloping, especially if the slope is over 12 degrees
  • Ground cover provided by vegetation
  • The distance to surface water
  • Weather conditions
  • The soil type and condition
  • The presence of land drains

Restrictions to spreading manufactured nitrogen fertiliser

There is closed period for spreading manufactured nitrogen fertiliser:

  • 15 September to 15 January on grassland
  • 1 September to 15 January on tillage land

There are some exceptions to this rule, such as winter oilseed rape, but there are still strict criteria about quantity of fertiliser and times. There are also exceptions for greenhouses and low-intensity farms.  Visit the government website to find out more.

Manufactured fertilisers or organic manures should be spread as accurately as possible and they should not be spread if a field is either:

  • Waterlogged, flooded or covered in snow
  • Frozen for more than 12 hours in the previous 24 hours

You must not spread:

  • Manufactured nitrogen fertiliser within 2 metres of surface water.
  • Manufactured nitrogen fertilisers within a 2-metre zone from the centre of an established hedge.
  • Organic manure within 50 metres of a spring, well or borehole or 10 metres of surface water.

You must only spread manufactured nitrogen fertilisers and manures on agricultural land that you’re using to grow crops (including grass).

Organic manure

Organic manures come from animals, plants or humans. Included in the term organic manure are:

  • Slurry
  • Poultry manures
  • Solid manures (such as farmyard manure, sludge cake or compost)
  • Sewage sludge (also called biosolids)
  • Other liquid manures (such as abattoir waste or anaerobic digestate)

Slurry is liquid organic manure that is produced by livestock (other than poultry) while in a yard or building. It includes animal bedding and water that drains from areas where animals are kept.

Storing organic manure

All slurry and poultry manure produced must be able to be stored in a yard or building for a closed period:

  • 1 October to 1 April inclusive for pigs and poultry
  • 1 October to 1 March inclusive for cattle, sheep, goats, deer and horses

This is all slurry produced by the farm that has not been:

  • Sent off your farm
  • Spread on your fields with low risk of runoff

While storing the slurry you produce, any rainfall, washings or other liquid that enters the store needs to be contained during the storage period.

Calculations for overall storage capacity, average rainfall figures for your postcode area, and understanding how much manure your animals will produce, can be worked out using the AHDB Slurry Wizard.

Equipment for spreading slurry

Slurry needs to be spread by precision spreading equipment

  • Low spreading trajectory (below 4 metres from the ground)
  • Maximum rate of no more than 1 millimetre per hour

Spreading organic manure

Some organic fertilisers are called ‘highly readily available nitrogen manures’; they have more than 30% of their total nitrogen content immediately available to crops.  Poultry manure is one of these.  There are restrictions as to when you can spread these manures on different types of soil, and the amount you can spread.

Separating slurry

Slurry that is being separated into liquid and solid parts must be fully controlled and monitored.  The stackable solid should either be stored under cover or on a concrete pad so that rainfall falling on it can be collected and stored.

Record keeping 

You need to keep comprehensive records of all manure and fertiliser application on your farm for a minimum of 5 years.  You also need to show where field heaps of FYM are stored on your Farm Risk Map.   

You will need to prevent water pollution from your farm whether or not your land is an NVZ.

For more information, full details and advice on what is required for NVZ planning, and for help and advice on all farming legislative matters speak to our farm consultants and NVZ planners at Douglas Green Consulting.

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