Paleocryogenesis as a Factor of Heterogeneity of Agro-Gray Soil

Delineation of the features of paleocryogenic microtopography by zero-curvature morphoisographs on a test plot in the south of Moscow oblast enabled us to reveal the polygonal-blocky microrelief (microelevations, microdepressions, slopes, and runoff strips), forming eluvial, trans-eluvial, and trans-accumulative agrolandscapes. The soil cover pattern of eluvial agrolandscape includes elementary soil areas of noneroded, slightly eroded, moderately eroded, and aggraded soils. The agrolandscape is dominated by noneroded soils. The soil cover pattern of trans-eluvial agrolandscapes with microdepressions includes elementary soil areas of slightly, moderately, and strongly eroded soils, as well as eroded–aggraded and aggraded soils, with the dominations of slightly eroded soils. The soil cover pattern of trans-accumulative agrolandscapes also includes elementary soil areas of slightly, moderately, and strongly eroded soils; eroded–aggraded soils; and aggraded soils with the domination of strongly eroded soils. The paleocryogenic microrelief became the initial factor of the formation of elementary soil areas with different erosion rates during the long-term (200 years) agricultural use of these lands. Elementary soil areas with different erosion rates of the upper horizons are characterized by outcropping of underlying horizons of different textures. We have identified silt loam, light clay, and clay loam exposed to the surface by erosion on the studied plot. As a result, a complex soil cover pattern with differentiation of soils at the level of varieties (in Russian soil classification system, a taxonomic category based on the topsoil texture) was formed.