The limit of 170 kg nitrogen per hectare is a specific requirement of the Nitrates Directive’s Annex 3.
However, the Directive also allows member states to seek a derogation from this limit (i.e. set a higher limit) if it can be demonstrated that doing so will not undermine the achievement of the environmental objective of the Directive. This is called a derogation from the directive’s limit of 170 kg N/ha.
For a derogation to be successful, it must ensure that a holding operating above the 170 kg N/ha poses no additional environmental risk, and is justified on the basis of objective criteria, such as, e.g. demands on a certain percent of the acreage available for manure application on the cattle holding shall be cultivated with grass etc. with low nitrate leaching potential, and that grass and catch crops shall not be ploughed before 1 March in order to ensure permanent vegetal cover of arable area for recovering subsoil autumn losses of nitrates and limit winter losses.
The Commission adopted the Danish derogation for the first time in 2002. This derogation was extended in 2005, 2008 and again in 2012.
In 2012, Denmark requested for a new extension of the derogation until 31 July 2016. The Danish derogation text is to be found in this document:
Derogation text from October 2012 (pdf file 34 kb)