Present and past soil erosion rates in catchments of the Kraichgau area (SW-Germany)

Abstract In four catchments of the Kraichgau area (SW-Germany), all covered with loess and distinguished by different combinations of natural and manmade erosion risks, total and recent soil losses from the hills were examined. The total loss was calculated as difference of quantities of soil material of the mapped soil units compared with a profile under erosion protection, the recent loss on the basis of young sediments in the depression, using contents of cadmium and lead to distinguish between old and young soil deposits in the depressions. In two of the catchments total soil loss from the hills came up to about 90% of the formerly existing Luvisol material. Total soil loss did not correlate with the natural erosion risks (inclination, slope length), but recent soil loss correlated with the manmade erosion risks (land utilisation type). This recent soil loss ranged from less than 14 t·ha −1 ·yr −1 in the catchment with terraced slopes to 84 t·ha −1 ·yr −1 in a catchment with a high percentage of corn and sugar beet on the cultivated area and with large fields cultivated downslope. In a similarly endowed catchment but with transversally cultivated fields a recent soil erosion of 39 t·ha −1 ·yr −1 was calculated. Methodical problems are discussed.