Assessment of surface soil loss on erosion prone slopes

The study was conducted to comparatively assess quantitative soil loss, calculated using field data and mathematical models. The work was conducted from 1985 to 2026 on erosion-prone slopes of a watershed used in a contour-reclamation farming experiment in the Kursk region. The soil cover consists of typical chernozems and leached heavy loamy soils. A mathematical model of water erosion was used to predict average long-term soil loss. The second assessment method was geoinformation, with calculations based on a universal equation for soil loss due to erosion and coefficients established for the Central Black Earth Region. The calculations were based on a digital elevation model of the studied watershed. Field data on soil loss were obtained at runoff sites and calculated using the water-based method. An increase in the share of continuous winter crops in the cropped area structure contributed to a reduction in soil loss due to runoff in the spring. Based on field studies, soil erosion losses in the study area averaged 3.79 t/ha from 1985 to 2005, with a peak of 21.7 t/ha. In 2006-2026, the respective figures were 1.89 t/ha and 16.3 t/ha. Calculations using a mathematical model indicate higher losses (4.9 ± 0.2 t/ha), indicating an overestimation of these figures. A water erosion model-based forecast of probable average annual soil loss, taking into account the changed structure of cropped areas for the catchment area as a whole, revealed a trend toward an increasing contribution of rainfall to total soil loss compared to snowmelt runoff. This is consistent with field survey results and does not exceed the permissible erosive soil loss (3 t/ha).