Phosphorus: P-Balance and P-Content in Soils

An indispensable nutrient for plants and animals, phosphorus (P) circulates in fairly large quantities in the plant and animal production sectors. Animals excrete excess phosphorus in their faeces and urine, which is later spread on fields as fertiliser. In plant production, excess phosphorus from fertilisers (farmyard manure and mineral fertilisers) accumulates in the soil.Phosphorus from the soil can, however, end up in surface waters if it is washed away with the topsoil or washed out of the soil into the groundwater or tile drains.

In small and medium-sized lakes this can lead to environmental problems (so-called eutrophication), since phosphorus strongly fosters algal blooms on the water surface. After the algae die, they are broken down on the lake bed by oxygen-consuming aerobic bacteria. Once sufficient oxygen is no longer available, anaerobic bacteria become involved in the decomposition process. These produce reduced and in some cases toxic substances such as hydrogen sulphide, ammonia and methane. The lack of oxygen and the toxic products can cause fish die-off. Prudent handling of phosphorus is not only important because of eutrophication, however: unlike nitrogen, phosphorus is a non-renewable resource. Furthermore, mineral phosphorus fertilisers are often contaminated with harmful substances such as uranium or cadmium.


Further Information

Agrarbericht 2012 (PDF, 14 MB, 23.03.2021)Bundesamt für Landwirtschaft (BLW)

Bodeneigenschaften und Bodenanalysen.
Flisch, R., Neuweiler, R., Kuster, T., Oberholzer, H., Huguenin-Elie, O., Richner, W., 2017. 2/
In: Richner, W., Sinaj, S. (Eds.), Grundlagen für die Düngung landwirtschaftlicher Kulturen in der Schweiz (GRUD 2017). Agrarforschung Schweiz. Agroscope: