‘There is no scientific substantiation for the strict manure standard in the Netherlands’

Establishment of manure standard

This Thursday, the House of Representatives will debate Dutch manure policy and derogation. What does this mean? In the Netherlands, Brussels allows us to spread a certain amount of manure on the land. This has been set at 170 kilos of nitrogen per hectare per year. But how did this number come about? Jaap Schröder, involved in the research when the legislation was created, explains.

“Someone at the European Commission stated, not entirely incorrectly, at the end of the 1980s that there was some kind of connection between high livestock densities in various areas in Europe and high nitrate concentrations in the groundwater. And then this gentleman realized that two large livestock units, a cow of a certain size, that is a good standard to reduce the nitrate level. And then he found that such a standard cow excretes 85 kilograms of nitrogen through feces and urine.” That 85 kilograms has been doubled, resulting in 170 kilograms of manure per hectare per year. “That standard does not have much more substantiation.”

The whole of the Netherlands is a nitrate-sensitive zone

Schröder further explains that the European member states had to apply this in their so-called nitrate-sensitive zones. The Netherlands designated the entire country as sensitive to nitrate leaching at the time, which is why the 170 kilogram standard applies throughout the Netherlands. The European Commission then stated that if it can be demonstrated that certain crops absorb a lot of nitrogen and the soil can convert a lot of nitrogen into harmless products, a derogation can be applied for. The Netherlands has this exception to this day, but is at risk of losing it.

After the standard was established, a large-scale study was conducted in Wageningen in which Schröder was a part. It was investigated whether the 170 kilograms was justified in the Dutch situation. “Our conclusion was no.” Schröder indicates that it was then up to the ministry to make a structural arrangement based on these publications, instead of a program for derogation once every four years. “That apparently didn’t happen.”