<p>The rate of soil losses on arable land depends to a large extent on the set of sown agricultural crops. Socioeconomic changes over recent decades have affected the range of crops cultivated in the agrarian regions of Russia, leading to changes in the soil-control indices of agrocenoses (C factor). The objective of the study was to identify changes in the C factor of crop rotations for periods of snowmelt and rainfall runoff during 1996–2012 and 2014–2022 at the level of administrative regions of the Russian Federation and their municipalities. The dynamics of cropland areas was estimated according to official statistical data. It was found that although the C factor of rainfall runoff grew during 1996–2012 in most regions, it became stabilized in the southern part of European Russia over the last decade. In the Volga region, the Urals and Siberia, the C factor of rainfall runoff continues to grow due to the increase in the proportion of row crops in crop rotation. However, the change in the C factor was below 20% across the most part of the regions in the past 30 years. A high variability of C factor values and trends was established at the level of municipalities. The C factor variability is at its lowest in the regions where chernozem predominates. The higher C factor in the period of rainfall runoff decreases soil fertility. The most vulnerable to soil erosion are regions where by the end of the 20th century soil losses from arable land were larger than elsewhere (Kursk, Orel, and Tula oblasts, the Republics of Mordovia and Tatarstan).</p>