Transformation of the Surface Layer in the Arable Soil Horizon under the Impact of Atmospheric Precipitation

The aim of this study was to analyze the transformation specifics of the surface layer in the arable horizons of chernozem, gray forest and soddy-podzolic soils under the impact of atmospheric precipitation. The research was carried out using soil samples collected at the key sites and the model experiment results. The soil surface condition, its color, micromorphological features and microtomographic structure, as well as the chemical composition of soil were analyzed. Atmospheric precipitation has been found to change the properties of the surface layer in the arable soil horizon. Changes in the mineralogy are pronounced in the redistribution of minerals between granulometric fractions. The longer the soil surface remains open to alternating precipitation and drying, the more pronounced is the formation of surface wash-out (eluvial) and wash-in (illuvial) microlayers differing in the content of fine dispersed organomineral substances and their structural arrangement. The initial state of humus and the soil texture predetermine peculiar features of microhorizons formed on the surface. In the upper part, a silty or sandy layer is formed with the minimal amount of microaggregates and fine matter; whereas below, the size and number of aggregates increase markedly. The revealed regularities must be taken into account upon remote sensing and mapping soil properties. To assess the humus content in the arable horizon, areal or satellite images of newly plowed and burrowed fields are required. The mineral composition, in turn, is detectable better using the images of transformed arable soil surface.