Scale dependent soil erosion dynamics in a fragile loess landscape

Loess landscapes provide highly fertile soils in temperate zones and thus are often under intensive agricultural use with a high susceptibility to soil degradation. Magnitudes of soil erosion on different spatio-temporal scales are hard to recognise or were even ignored due to the restricted human perception. Precise and reliable soil erosion measurements are still very scarce, especially for intense single precipitation. In this study, present-day soil erosion is investigated as a complex process on different spatial and temporal scales, such as a short-term observation on plot scale and a medium-term observation on slope scale, which lead to long-term indications for the catchment scale. Classical soil drillings, 7Be and 137Cs radionuclide tracer investigations and non-invasive unmanned aerial vehicle (UAV) photogrammetry were performed for two cultivated field sections within the Saxon Loess Province (Eastern Germany). The main findings are: (1) for a short-term intense precipitation event interrill soil erosion reaches up to 4.69 ± 0.73 mm on plot scale and mean total erosion values reach 1.45 mm on catchment scale; (2) medium-term soil erosion exhibit values up to 33 cm on slope scale within the last 50 years, indicating a strong landscape liability to agricultural use; (3) climatic pressure with increasing temperature and precipitation shifts towards seasons with bare soil surfaces favours the soil erosion process and increases the fragility of the landscape substantially. In conclusion, soil erosion is the driving factor of present-day landscape evolution in the Saxon Loess Province.