The Dutch livestock produces not only milk and meat, but manure too.
Manure is a fertiliser, it contains nutrients (minerals) for crops to grow.
Part of these nutrients is not absorbed and leaches into the ground water and surface water, polluting the environment.
This is why the European Union sets standards by which member states can regulate how much manure farmers are allowed to use on their land.
In addition to the EU application standard for nitrogen from animal manure, the Netherlands has its own standards for the total amount of nitrogen fertiliser, which exceed the standard for manure.
The farmer can supplement the difference between the two with chemical fertilisers.
Under certain conditions the EU allows Dutch farmers, as well as farmers in several other countries, to use more manure than the EU standard.
This is called derogation from the Nitrates Directive.
In order to qualify for derogation, farmers must cultivate at least 80% of their area as grassland.
Grass absorbs the nutrients better than crops like corn.
This means there is less leaching of nutrients into groundwater and surface water.
Derogation provides farmers with financial benefits in two ways.
Firstly, they have to spend less on the removal of manure away from their farm, secondly they don’t have to buy as much chemical fertilisers.
With the Minerals Policy Monitoring Programme, RIVM has been measuring water quality on 300 derogation farms since 2006.
Wageningen Economic Research collects information about agricultural practices and fertiliser use.
These monitoring programmes demonstrate that the use of more manure by derogation farms does not have a negative impact on water quality.
This is due to the fact that the total amount of admissible fertilisers has not increased.
In addition, the use of land as grassland is promoted, which helps decrease nutrients leaching.