Abstract: Specific features of soil salinization in the Ekhiin-Gol oasis,one of the largest oasis in the Transaltai Gobi of Mongolia,were first studied in 1977.It was shown that recent hydromorphic solonchaks forming as a result of modern salt accumulation predominate in the soil cover of the oasis.A detailed map of soil salinization was compiled,and specific features of salinization in different soils of oases in the Gobi Desert were studied.In 2001,the soil survey of the oasis was repeated,which made it possible to trace the dynamics of soil salinization within a 25-year-long period.The comparison of the data on the soil salinization in the Ekhiin-Gol oasis obtained in 1977-1978 and 2001 has shown that the main part of the oasis area occupied by hydromorphic solonchaks has not undergone significant changes in the degree and character of soil salinization.The rise in the salinity of the oasis soils is most pronounced in the area of the initially(1977) nonsaline or slightly saline meadow and meadow swamp hydromorphic soils and in the area of the formerly irrigated and then abandoned lands.The rise in the degree of the soil salinization may be caused by both natural factors(a drop in the general water supply of the oasis) and natural-anthropogenic factors(a decrease in the discharge of the springs and a lower amount of water accumulated on the soil surface in the form of icings in the winter seasons).The secondary salinization of the irrigated lands is locally developed.It is probably related to saline rocks underlying the loesslike loam.These rocks become the source of soil salts as a result of irrigation.Secondary salinization is sometimes actively developed upon irrigation with saline water from deep wells within the irrigated lands.The tendency for an increase in the degree of soil salinization may also be related to the plant cover degradation as a result of overgrazing.It leads to the formation of barrens,which enhances the physical evaporation from the soil surface and may activate salinization processes in the oasis.