In autumn, plant need for nitrogen is usually small, as quite often, a surplus of nitrogen is left in the field from the preceeding crop. Moreover, mineralisation takes place during the autumn months, especially in warm and humid climates. Therefore, in nearly all Member States, manure application/fertilisation in autumn and winter is legally restricted as a national measure of the Nitrates Directive. In case there is no legal regulation, the degree of manure applied in autumn could reveal the degree of pressure for animal breeders to get rid of some of the organics produced.

With the indicator quantity of manure applied in autumn the amount of nitrogen applied with a high risk of N-transfer could be estimated. However, the data to calculate this indicator derive from the farm individual fertilisation plans. They are therefore confidential, and hard to obtain, especially when legal restrictions grasp.