Abstract: Buzhai-nur Lake is a representative salt lake in the hinterland of Mu Us Sandy Land. Flat and bare sandy lakeshore zone, lakeshore dune and semi-fixed dunes are widely distributed to the southeast of Buzhai-nur Lake. Abundant sand and dust that deposited on the surface of dry lake, are salt-rich and highly susceptible to saline-alkaline dust emission, threatening the ecological environment in the downwind areas. In this study, the grain-size and physicochemical characteristics of surface sediments within 0-2.5 km to the southeast of Buzhai-nur Lake were studied, aiming to provide basic scientific reference for the prevention and ecological management of the source area of saline-alkaline dust storm. Results show: (1) Surface sediments at the playa are predominantly coarse, medium and fine sand; (2) With increasing distance from the center of the lake, the fractions of coarse sand and fine sand decrease while the very fine sand, silt and clay gradually increase, and the medium sand dose not significantly change; (3) Soil moisture and bulk density of surface sediments increase, but pH, total salt content and electronic conductivity decrease as the distance increased from the center of the lake. Overall the results indicate that alkalization is serious in this area and the physicochemical properties exhibit remarkable trends in the downwind direction. Soils in the lakeshore zone have experienced significant wind erosion, which may be the important provenance of saline-alkaline dust storm and the formation of sand dunes in the lakeshore.

Key words: Buzhai-nur, dry lake bed, soil grain-size, physicochemical characteristics