Abstract: Based on the similarity theory of wind and sand movement,the study took the Tamarix nebkhas and interdune plants,which are widely distributed in Oasis-desert ecotone at the southern rim of the Taklimakan Desert,as the research prototype to create five sets of nebkhas model with background vegetation coverage of 0%,4%,10%,16%,26%,respectively to conduct the simulation experiment of erosion and accumulation change rule in the wind tunnel.The results show that:erosion and deposition distributions among Tamarix ramosissima nebkhas and interdune can be divided into six areas:depositional area in front of nebkhas, the eroded area on nebkhas' windward slope, the eroded area on nebkhas' both sides, the vortex depositional area on nebkhas' leeward side, the wake depositional area behind the nebkhas and the unaffected area. Along with the increase of the wind speed, range of frontal depositional area and wake depositional area shrinks while that of the eroded land on nebkhas' both sides decreases significantly. In addition, along with the increase of background vegetation cover range of frontal depositional area and wake depositional area increased while that of eroded land on nebkhas' both sides decreases significantly. The entirety erosion area ratio, the wind erosion rate and the erosion/accumulation intensity on the partitions are all decreasing with exponential law. When the background vegetation coverage equals to 0%, wind erosion rate in nebkhas-affected area is obviously higher than that non-nebkhas-affected area, which indicates that the presence of nebkhas will increase the wind erosion on bare surface. When the background vegetation coverage equals to 4%-16%, the wind erosion rate of the nebkhas-affected area was lower than that of the non-nebkhas-affected area, which means that the presence of interdune vegetation around nebkhas could, to a certain degree, make contribution to wind breaking and sand blocking. When the background vegetation cover is over 16%, change of the erosion intensity and wind erosion rate of Tamarix ramosissima nebkhas and interdune become level off. It is considered that keeping the background vegetation coverage not less than 16% is the key to the scientific conservation of theTamarix nebkhas in the Oasis-desert ecotone.

Key words: Tamarix ramosissima nebkhas, change of erosion and deposition, background vegetation coverage, wind tunnel simulation