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Considering the Merits of a NAP Derogation

February 18, 2021

College of Agriculture Food & Rural Enterprise (CAFRE) Adviser, Dr Alastair Cameron discusses the Nutrients Action Programme (NAP) Derogation and the various options currently available to farmers to comply with the Nitrogen Loading limit of 170kg of nitrogen per hectare per year (kg N/ha/year) from livestock manure.

Nitrogen Loading is a key component of the NAP and is a measure of stocking rate which has an upper limit of 170kg N/ha/year. The CAFRE N Loading Calculator, which is available at can be used to calculate your N Loading.  Many farms that have a N Loading above the limit of 170kg N/ha/year have adopted different ways of lowering it, through a combination of exporting slurry, renting additional land and reducing livestock numbers.  These are viable options, however, they are increasingly expensive and less viable for higher Nitrogen Loadings especially when this exceeds 200kg N/ha/year.

If you have a Nitrogen Loading above 170kg N/ha/year, you should consider applying for a NAP Derogation, which will allow you to operate up to a limit of 250kg N/ha/year from grazing livestock manure. The NAP Derogation is available if you keep cattle and sheep, but in practice it mainly applies to intensive dairy farms. It allows farms to operate at a higher stocking rate whilst protecting the environment and water quality in particular.  Operating under a NAP Derogation enables you to continue to operate with the same levels of livestock and area of land (up to 250kg/ha limit).  Consequently, there are additional rules to ensure that the higher stocking rate does not pose a greater risk to the environment.

Derogated farms must plan and record manure and fertiliser applications by preparing a fertilisation plan and submitting a fertilisation account each year. You can keep these records yourself or you can employ a consultant to help.  There are crop rotation & soil management restrictions which help to minimise the loss of nutrients from the soil and reduce leaching. Derogated farmers are encouraged to apply the bulk of their slurry early in the season, and must apply at least 50% by the 15 June each year. This is to coincide with the time when grass growth is at its peak and nutrient uptake by plants is at its optimum. Derogated farms are also encouraged to use Low Emission Slurry Spreading Equipment (LESSE) all year round to increase nutrient efficiency, but must use it for all slurry applications after 15 June each year. Derogated farms must also have at least 80% of the agricultural area in grassland and maintain a Phosphorus Balance of no more than 10kg P/ha/year to be eligible for a NAP Derogation. Water quality is a major issue in Northern Ireland and high stocking densities can increase the risk of nutrient run off to waterways. Alastair states that “If you want to maintain a higher stocking rate and look after the environment you should apply for a NAP Derogation.”

Alastair compares the alternatives to a NAP Derogation which can reduce the Nitrogen Loading to under 170kg N/ha/year, such as exporting slurry to other farms. If you are significantly above the 170kg N/ha/year limit this could be an expensive option. Finding suitable land, cost in transporting slurry and the loss of nutrients in the slurry are hidden costs. Exported slurry, if replaced with chemical fertiliser is an extra cost to the farm. Records of slurry exports must also be submitted to NIEA each year.

On the other hand you could consider renting additional land. The additional cost of renting land could be substantial, depending on local demand.  Suitable land may not be available nearby and additional transport costs should also be taken into account.

You could also consider cutting livestock numbers to reduce the Nitrogen Loading to under the 170kg N/ha/year if you are close to the limit. If you are significantly above the limit, the fall in profitability would be proportionally greater as many fixed costs would not reduce in proportion to the reduced herd size.

When you weigh up the costs and difficulties of exporting slurry, renting additional land and reducing livestock numbers, applying for a NAP Derogation may be the most cost effective option to comply with the regulations and protect the environment, if your Nitrogen Loading is significantly above the 170kg N/ha/year limit. 

You can apply for a NAP derogation at  The deadline for applications and submission of accounts has been extended to 31 March 2021* due to the COVID 19 pandemic.  This extension will allow you additional time to discuss applying for a Derogation for 2021 with your CAFRE adviser or agent.  It will also allow more time for the preparation of fertilisation accounts by those farmers who availed of a NAP Derogation in 2020.  The revised NAP Derogation Guidance 2019-2022, NAP Derogation Fertilisation Plan 2019-2022 and NAP Derogation Fertilisation Account 2019-2022 booklets are now available at

*31 March deadline applies for the 2021 year only