80 % or more of the area available for manure application on farms shall be cultivated with grass. Farmers benefiting from an individual derogation shall carry out the following measures:

1. (a)

   temporary grassland shall be ploughed in spring;

2. (b)

   ploughed grass on all soil types shall be followed immediately by a crop with high nitrogen demand;

3. (c)

   crop rotation shall not include leguminous or other plants fixing atmospheric nitrogen. This however will not apply to clover in grassland with less than 50 % clover and to cereals and pea undersown with grass.