REGULARITIES GOVERNING THE EVOLUTION OF THE SOIL MANTLE AND THE PROPERTIES OF STEPPE AND DESERT SOILS IN MONGOLIA

The regularities of the soil mantle formation in Mongolian plains and mountains under extremely continental arid and semiarid climatic condi tions are outlined. Chestnut soils of the dry steppe zone and brown ar id and gray-brown desert soils predominate in the soil mantle of Mongo lian plains. Specific features of the soil mantle and soils of Mongoli an steppes and deserts are determined by modem pedogenesis along with paleogeographic events in the Central Asian region. A low proportion o f saline soils in the soil mantle and rare occurrence of soluble salts in the profiles of zonal soils are identified as specific regional fe atures of Mongolian steppes and deserts. They are explained by the spe cific features of the soil-forming rocks, i.e., by the small participa tion of saline deposits among parent materials in the desert and stepp e zones of Mongolia.