Why do nitrates kill fish

Nitrate in groundwater - what does agriculture have to do with it?

In order to better protect drinking water and the environment, the use of fertilizers must be reduced to an acceptable level. This is regulated by law primarily through the Fertilizer Ordinance. It tells farmers how to use fertilizers.

The fertilizer ordinance has been discussed a lot in recent years. The EU has been accusing Germany for a long time that the provisions of the previous fertilizer ordinance could not sufficiently reduce water pollution in this country, and therefore sued Germany in 2016 before the European Court of Justice. In response to this, the regulation was again extensively revised in 2017, and at renewed pressure from the EU, in 2020.

The current version now contains much stricter regulations. For example, uniform fertilization planning is mandatory for all farmers. This is to ensure that only as much fertilization is used as the plants can actually absorb. In addition, the periods during which no fertilizers can be applied have been extended in winter.

In the areas polluted with nitrate - the so-called red areas - stricter rules will apply from 2021: All intensive farms in these areas must reduce fertilization by a fifth.

While the EU was finally satisfied, the second tightening of the fertilizer ordinance in 2020 led to violent farmers' protests in the country. German farmers consider the tightening to be exaggerated and see agricultural production in Germany at risk as a result.

Avoid nitrogen loss

Decreasing the amount of fertilizer is one way to deal with the nitrate problem. Another is to make sure that as little as possible of the nitrogen applied is lost. This can be achieved, for example, with catch crops such as green rye or winter rape. These are plants that cover the arable soil - or at least part of it - even in the cold season. They use the fertilizer nutrients in the soil for their growth and thus prevent them from being lost in the groundwater.

Another method is to do without the plow and work the soil as little as possible. The expert speaks here of ploughless or conservation tillage. This destroys the natural soil structure as little as possible and thus reduces the risk of superficial loss of nutrients due to wind or water erosion. But a lot can also be achieved through technology. For example, by working the manure directly into the ground with a suitable device. Today there are machines for this that loosen the soil and bring in the liquid manure in one operation.