Based on field experiment and comparative analysis

physical and chemical properties of soil crust at the base of the Salix gordejevii sand barrier with row spacing of 5 m and 8 m and at 2 m away from the base(for contrast) are investigated.Results show that soil is alkaline at the base of the two row Salix gordejevii sand barrier

while soil at 2 m away from the base is acidic.The soils in the 5 m and 8 m row spacing sand barriers do not have significant difference in pH value.The content of organic matter

total N

and total P at the base of the sand barrier are greater than the contrast.Compared with the base and the location 2 m away from the base

available nutrients in both 5 m row spacing and 8 m row spacing are higher and available N are lower than the contrast.Both available N and available P in 8 m row spacing sand barrier are greater than those in 5 m row spacing sand barrier.The formation of soil crust in the Salix gordejevii sand barrier is a physical process which takes sand grains as skeleton and fill soil pore space with the fine kernel(d0.02 mm).