Map of soil erosion risk in Switzerland

The Soil Erosion Risk Map gives a national overview on the erosion risk of Swiss soils, particularly for arable land. With the help of an adapted version of the empirical erosion model USLE (Universal Soil Loss Equation), the long-term soil erosion risk was calculated all over the country in a hectare grid. The Soil Erosion Risk Map is meant to serve as a basis for the Cantons to create detailed maps or investigate in depth areas that are particularly at risk. Under the assumption that within the current crop rotation all arable land is ploughed and no cover crops are cultivated, long-term average soil loss is less than 2 t/ha and year on 61 % of all arable land, and may be classified as low erosion risk. 22 % are in the critical range between 2 and 4 t/ha and year, and 17 % with more than 4 t/ha and year may be described as having a high risk of erosion. The spatial distribution of the erosion risk shows a highly heterogeneous pattern within the main regions of arable farming, and no specific high-risk region could be identified. In a scenario calculation in which ploughing is replaced by no-tillage and winter fallow by cover crops on all arable land, the risk of soil erosion is reduced on average by about two thirds.