Multiscale Estimates of Soil Erodibility Variation under Conditions of High Soil Cover Heterogeneity in the Northern Forest-Steppe of the Central Russian Upland

Abstract

The study of soil erodibility, i.e., its ability to resist the destructing action of water flow and raindrops, is one of the important challenges in erosion science. The values of soil erodibility are used in erosion models and make it possible to calculate the rate of soil matter loss/accumulation. The purpose of this study is to assess soil erodibility and its variation on plots of different areas in the northern forest-steppe of the Central Russian Upland. It has been established that the calculated parameter of soil erodibility (K-factor) is mainly determined by the soil organic matter content. The mean K-factor for gray forest soils is more than 1.5 times higher than that for noneroded chernozems. The K-factor increases with an increase in the degree of soil erosion. For example, in a series of noneroded and slightly, moderately, and strongly eroded chernozems, it reaches 38, 42, 44, and 57 kg h/(MJ mm), respectively. Gray forest soils are much more susceptible to the risk of degradation from erosion than chernozems because of their higher erodibility and lower thickness of the humus layer, other factors being equal. The use of different methods of K-factor interpolation exerts little effect on changes in the mean soil erosion rates calculated by the WaTEM/SEDEM model, even under conditions of the highly contrasting soil cover. With a change in the scale of soil erosion estimates (the transition from a medium to a large scale, or from a large to a medium scale), the deviation of calculated mean soil erosion rates is less than 15%.