Nitrogen is a valuable fertiliser, but is nowadays experienced as a problem. This is mainly due to the negative effect on natural reserves. Research by the Dutch advisory council (Raad van state) showed that the amount of nitrogen in protected natural reserves has hardly decreased since 2015. The Dutch edict on tackling nitrogen (PAS) did not work sufficiently. The conclusion was simple: the Dutch approach to nitrogen was insufficient and had to be adjusted.
Nitrogen is mainly a problem because it causes eutrophication. This affects the biodiversity in these natural reserves. Nitrogen constitutes of two substances that are harmful to the environment: ammonia and nitrogen oxides. Too much ammonia in the soil causes acidification and too much nitrogen oxides in the air can cause smog and the formation of particulate matter. These last two forms of air pollution are directly harmful to people. For example, people can experience lung problems or have an increased chance of getting sick. Particulate matter is not only harmful to the lungs, but can also lead to cardiovascular disease.
Degradation of biodiversity
The fact that nitrogen affects biodiversity sometimes leads to confusion. Plants need nitrogen in order to grow. However, a surplus of nitrogen causes certain plants to grow excessively. These crops are nitrogenous crops, such as grass or nettles. Because these plants have excellent resistance to nitrogen, they grow so fast that other plants no longer have a chance. This also has consequences for animals that depend on these plants: insects and butterflies disappear along with, for which moorland is a good example. For aquatic plants and fish, too much nitrogen leads to a decline in biodiversity. Algae are also nitrogenous plants. When too much algae grows in the water, the amount of oxygen decreases.
Steps have already been taken in the past to combat excess nitrogen in the environment. Policy was drawn up between 1990 and 2010, which resulted in a significant reduction in nitrogen emissions. However, research by RIVM shows that after 2010 this decline stagnated. The policy that was drawn up in the past is therefore no longer adequate nowadays. When we look at this problem in a European context, it becomes clear that something really needs to change in our nitrogen policy. Dutch nitrogen emissions are the highest in Europe. We emit approximately four times as much nitrogen per hectare as the European average. However, our nitrogen problem is not just a Dutch problem. Because nitrogen ends up in the air, the Netherlands has become an 'exporter' of nitrogen emissions. According to the National Institute for Public Health and the Environment (RIVM), the majority of our pollution is blown abroad.
The RIVM also shows that Dutch agriculture accounts for the largest share of nitrogen emissions. 60% of the domestic production of nitrogen comes from agriculture. When looking at the total nitrogen emissions in the Netherlands, agriculture still accounts for 40%. By way of comparison, Dutch car traffic accounts for 15% of emissions.
Emissions from Dutch agriculture consist for the most part of ammonia. Ammonia is created when urine and manure from stable animals come in contact with each other and mix. A single cow in a stable, for example, produces 11 kilograms of ammonia per year. A cow that is allowed to go out to pasture emits 9.5 kilograms of ammonia per year.
The nitrogen problem therefore consists of a number of components. Biodiversity in natural reserves is declining, people get sick more easily as a result of air pollution and the Netherlands is exporting the pollution to other countries via the air. Finally, it appears that the old nitrogen approach is no longer sufficient. Figures from RIVM show that agriculture is the largest producer of nitrogen, so it is logical that a nitrogen policy focuses mainly on this sector.