The specificities and properties of soils of solonetzic complex on the latest stages of development in the area of Caspian Sea region

The basic properties of solonetzic soils of (Early Khvalyn) part of Caspian Depression were investigated. This area is characterized by the absence of significant hollow microtopography, specific for the North of Caspian Sea region. Despite the actual poor significance of microtopography there is a specific for Post-khvalyn plain contrast threefold complex soil cover with deeply washed meadow-chestnut (dark-colored soils), light chestnut solonetzic soils and solonchak solonetzes. Such complexes are widely spread in the North of Caspian Sea region and they are related to the heights of 35-50 m above sea level. The combined investigation of the microtopography and soil density is conducted at two key plots, which are located in the region of Lepekhinka (Saratov Oblast) and Borsi (Western Kazakhstan) villages. The present flatness of the microtopography is caused by the flattening of the surface of Post-khvalyn valley during its evolutionary development, mostly due to microhighs sinking. The sinking is caused by the compaction of the initially loose extremely salinized soil material of sub-solonetzic layers of solonchak solonetzes (with “pseudo-sand” structure) as a result of long-term impact of capillary fringe on sub-solonetzic layers during the period of ground waters rising. The properties of desalted dark-colored (meadow-chestnut) soils in that case have a relict character and inherent from the previous stages of the territory development. These stages were characterized by the increased moistening of these soils due to significant hollow microtopography.