Similarities and distinctions in the genesis of salt-affected soils in different regions of the south of Eastern Siberia

Abstract

Soil salinization is determined by a set of factors, which can be subdivided into sources and mechanisms. The south of Eastern Siberia is characterized by the mountainous topography with numerous intermontane depressions, a large number of tectonic faults and springs. Hydromorphic surface-saline soils of sulfate and chloride-sulfate chemistry predominate. In Tuva, the share of chloride salinity increases, which is associated with the presence of salt rocks, and the percentage of soda-saline soils decreases sharply. In Buryatia, the percentage of soda salinity is higher than in other regions. In Khakasia, despite the gypsum deposits, the percentage of soda-saline soils is also significant, which is related to irrigation practices. Sharper differences are observed in individual basins of the regions, the salinity of which is determined by the presence of salinization sources in the given area, as well as by the mechanisms and conditions of soil salinization. For example, the presence of permafrost prevents the leaching of chlorides from the profile leading to the development of chloride salinization, or an increase in the alkalinity associated with the magnesium bicarbonate in slightly arid intermontane depressions of Buryatia and high–mountain depressions of Tuva.