Abstract: An accumulated sandbelt formed along the oasis edge, especially at the upwind places of the desert area in Gansu Hexi of China during the process of desert control in recent 60 years. The accumulated sand-belt is a byproduct of desertification combating through afforestation and barriers-setting. This paper analyzed the data (including wind velocity/direction) of 21 sites on the accumulated sandbelt to evaluate its stability and ecological effects. The results showed that the accumulated sandbelt is in a stable state. It plays a significant role in weakening wind and this effect is enhanced with the increase of wind velocity. The height of accumulated sand-belt is an important factor characterizing its windproof function. When the wind velocity is bigger than 2 m·s^-1, the windproof area in the downwind places is 20 times greater than the height of the accumulated sandbelt. When the wind velocity is bigger than 8 m·s^-1, the wind velocity on the top of the accumulated sand-belt is less than that in the upwind open areas. When the air flow reaches the windward slope, its energy is released and reduced by uplifting along the slope and diversion towards the two wings. Wind deflector reduces the velocity of the prevailing wind on the windward slope.

Key words: Xiangcheng, selenium, growth, AsA-GSH cycle.