At a glance
- The five-year average of nitrogen surplus per hectare of utilized agricultural land has decreased by 15 % since 1993.
- The Federal Government aims to reduce the average nitrogen surplus of the years 2028 to 2032 to 70 kilogrammes per year.
- Efforts must be considerably intensified to reach this target.
Nitrogen is an essential nutrient for all living organisms. However, excessive input of reactive nitrogen compounds to the environment has serious effects on the climate, biodiversity and landscape quality. For example, nitrogen which is not utilized by plants may lead to pollution of the groundwater, nutrient enrichment (eutrophication) of waterbodies, acidification of terrestrial ecosystems and the formation of greenhouse gases. An introduction to the issue of nitrogen surplus is given in the publication ’Reactive nitrogen in Germany‘ (UBA 2015).
In Germany problems occur especially in regions with high livestock density: Due to the high amount of farm manure in the form of animal excrements, often more nitrogen is applied to the fields as the crops can convert into biomass. The nitrogen surplus is an indicator of the potential nitrogen losses from agriculture to the environment.
Assessing the development
Between 1993 and 2015, the 5-year average nitrogen surplus decreased by around 15 %. Farmers are therefore using nitrogen more efficiently, the area of cultivation of high-output crops has increased and feed conversion by domestic animals has improved. However, the nitrogen balance indicates that only half of the total nitrogen input is removed by agricultural products (BMEL 2019, Statistical Monthly Report 06/2019, p. 502, in German only).
In the Strategy for Sustainable Development of 2002, the Federal Government set itself the aim to reduce the three-year average nitrogen surplus to 80 kilogrammes (kg) per hectare and year by 2010. This target has clearly been missed. A new target has been set in the revised version of the Sustainable Development Strategy in 2016: a maximum nitrogen surplus of 70 kg per hectare in average for the years 2028 to 2032 (BReg 2016). The German Fertilizer Application Ordinance, extensively revised in spring 2017, is intended to support the achievement of this goal.
According to current estimates, the German Environment Agency assumes that neither the revised Fertilizer Application Ordinance, nor the new targets of the German Sustainable Development Strategy are sufficient enough to preserve soil, water, air, climate and biodiversity extensively (cf. ‘Eutrophication of the North Sea/Baltic Sea by nitrogen’ indicator). This estimate was further reinforced by a judgement by the European Court of Justice against Germany for violating the EU nitrate directive in June 2018. As a result of the ruling and to prevent fines that have to be paid to the EU, key issues of the Fertiliser Application Ordinance has been revised in spring 2020. Again, these changes are expected to be insufficient. Numerous suggestions for further reduction of the surplus have been made by the German Advisory Council on the Environment (SRU) in an expert report (SRU 2015).
The nitrogen surplus is the difference between the input (e.g. fertiliser, feed, seed and seedlings, atmospheric inputs) and the output (animal and plant products) of the national farm-gate balance. A detailed description is given in Bach et al. 2011 (in German only). The data are published annually by the Federal Ministry of Food and Agriculture (BMEL). In order to adjust for annual fluctuations a five-year moving average is calculated from the values of the individual years with the two previous and two following years.
More detailed information: 'Nährstoffeinträge aus der Landwirtschaft und Stickstoffüberschuss' (in German only).