关键词: 绿洲-沙漠过渡带, 沙物质, 理化性质, 空间差异, 策勒

Abstract:

Topography and vegetation cover can influence physicochemical properties of aeolian soils in desert area. We made an analysis on physicochemical properties of sand materials on the surfaces of three aeolian landforms (the top of Tamarix nebkhas, the top mobile sand dunes, and the bare flat sandy land) from shifting sandy land to oasis along prevailing wind direction in Cele, Xinjiang, China. The results show that the range of mean grain size on the top of mobile sand dunes is between 2.6 Φ and 3.47 Φ, which is obviously coarser than on the surface of flat bare sandy land and Tamarix nebkhas. The sands trend to be finer from frontier shifting sandy land to the margin of oasis. The mean grain size of sand materials on frontier flat bare sandy land is 0.44 Φ coarser than that on fixed sandy land near oasis. The sorting of sand particles has no obvious differences in space. The skewness of sand particles on the surface of flat bare sandy land and on the top of mobile sand dunes is in the range from -0.06 to 0.06, which is symmetrical compared with average grain size. The skewness on the top of Tamarix nebkhas is in the range from 0.05 to 0.25, most of their skewness belongs to very fine skewed. The sand particles on the top of mobile sand dunes and flat bare sandy land show leptokurtic and sand particles on the top of Tamarix nebkhas show mesokurtic. Most of the pH of sand particles on the top of Tamarix nebkhas are sour, the rest of pH on other landforms are alkaline. The salt volumes have close relationship with aeolian landform. The total salt volumes in different landform units show that Tamarix nebkhas were more than flat bare sandy land and mobile sand dunes gradually, the salt volume on the top of mobile sand dunes are lowest. The total salt volumes become more and more with the decreased distance to oasis.

Key words: oasis-desert ecotone, sand materials, physicochemical property, spatial difference, Cele