Overfertilization

What is fertilizer?

Fertilizers are substances that help plants grow and produce more. They can be natural or synthetic. Water, carbon dioxide, and sunlight are all fertilizers by that definition, but they are typically omitted from fertilizer discussions since they are given rather than added by humans.

As previously mentioned, there are two forms of fertilizer: organic and inorganic. Nitrogen fertilizers, which are based on nitrate, are the most widely used chemical fertilizers in Europe. Animal waste, for example, is an example of organic fertilizers.


What is so bad about fertilizer?

Sounds sweet, right? Substances that aid plant growth. So, what’s the big deal with fertilizer? Or should I say, overfertilization?

Methane, carbon dioxide, ammonium, and nitrogen are among the compounds and chemicals contained in them. Today’s heavy use of fertilizers releases dangerous greenhouse gases into the atmosphere. Not only that, but overfertilizing causes the plants to be unable to use all of the nutrients, and the excess fertilizer seeps into the ground and surface water.


On the side you can see the risks of excess nitrogen use in a graphic. As you can see nitrogen can seep into the ground and surface water, posing serious environmental, animal, and human health risks. Nitrogen fertilizer is dependent on nitrate, which has been shown to be carcinogenic in large doses.

Another problem is that long-term overapplication of ammonium-based nitrogen fertilizers may cause soils to become acidic and introduce excess salts, which reduces the crops’ ability to absorb water, resulting in damaged roots, draught stress, and eventually crop death.


What’s being done against it?

Germany has implemented a nitrogen limit, which determines how much fertilizer may be used in a given field while also requiring farmers to log the amount of fertilizer used and maintain a certain distance from any surrounding surface waters.

However, this cap is still much too low to make a significant difference. Germany’s amendment to fertilizer legislation was deemed inadequate by the European Commission, and it was recommended that it be revised again. That was in 2018, and Germany has been required to pay hefty fines to the European Commission every year since then.

The FAO recently released a graph depicting global nitrogen fertilizer production from 1961 to 2014.

As you can see, the amount of nitrogen fertilizer produced in Europe has decreased in recent years, but it is still much too high to be considered sustainable.

When looking at a map of Germany, it is obvious that there is a problem with overfertilization.

Figure 1: Surplus of the nitrogen-area balance in German districts, averaged from 2015 to 2017. Right figure: Changes in nitrogen region surplus from 2015 to 2017 relative to the average from 1995 to 1997

Thankfully, France and Slovenia do not over fertilize as much as Germany.

This is partly due to the fact that those countries do not have many pig farms.


What else could be done?

The EU launched several initiatives to promote the use of less fertilizer, one of which is the Global Fertilizer Day, which takes place on October 13th.

The outbreak of the Covid-19 pandemic in 2020 resurrected the issue of food security. Agricultural workers played a vital role in ensuring that food was grown and delivered to every table during the lockdowns enforced in various countries. The Global Fertilizer Day honors their efforts.

EU Nitrogen Expert Panel

They also established the EU Nitrogen Expert Panel (EUNEP) to promote fertilizer efficiency in order to maximize plant growth while minimizing environmental effects. For example, to promote efficient nitrogen use, the published a nitrogen use indicator.

Furthermore, Germany could raise the nitrogen limit to prevent further overfertilization and to avoid paying penalties to the European Commission, allowing the money to be put to better use.


Micronutrient Fertilizers are another initiative. It’s a fertilizer made mostly of recycled nutrients, such as wastewater. As compared to nitrogen fertilizer, it releases fertilizer at a slower and more regulated pace. As a result, there are almost no extra nutrients that might leach into waterways. Overall, it will be one of the most long-term options.

Slow-release fertilizers may not trigger growth bursts as quick-release fertilizers do, but they do allow more plants to survive because they are not stressed. Due to the slower growth it also improves plant health, making them less vulnerable to disease and allowing them to root better.

Slow-release nitrogen fertilizers are more costly than quick-release synthetic fertilizers, but they have many advantages, including a lower risk of turf burning, more even, continuous plant growth, and less leaching into ground and surface water.


Overall, overfertilization is a major problem, but it is one that we can address together.