SWAT Model Application for Predicting of Water Erosion of Kastanozems Under Different Land Uses

The Kastanozems occupying the sloped lands of the Danube watershed in North Bulgaria are imposed to the risk of soil water erosion. The long-term field experiments carried out in the experimental field near the village of Trastenik in the Ruse region provided a valuable information on the run-off and soil losses under different management practices and grown crops. In order to enlarge in space and time information for the soil erosion processes, we applied the SWAT model (Arnold et al., 2012) on a small watershed including the territory of the experimental field. The simulations were carried out using long-term (1961–2022) climate data. The digital elevation model was used for delineating sub-basins, while soil and land use maps were used for delineation of the hydrological response units (HRU). Three scenarios for the agricultural lands were investigated—continuous growing of winter wheat or maize and crop rotation. The outcomes of the model were compared with the available measured data for the run-off and soil erosion losses under maize and wheat, and a reasonable coincidence was found.