Study on Mechanism Between Natural Shrub-grass and Soil Wind Erosion

Through field investigation on wind speed,aerodynamic roughness,rate of sand transporting and the structure of wind-sand flow on different underlying surfaces,we found that vegetation cover can prevent soil wind erosion effectively.Compared the fixed sandland whose vegetation coverage is 40% to the drifting sand dune which has no coverage,the average wind speed at the height of 0.2 m reduced 45%,the time of threshold wind velocity of soil erosion kept on reduced 83%,while the threshold wind velocity of soil erosion increased 70% and aerodynamic roughness increased 190 times;Compared to the drifting sand dune,when the speed of wind-sand flow is similar,the rate of sand transporting on semi-fixed sandland reduced 79.4%,while fixed sandland reduced 95.6%.The results indicated that a single plant can reduce wind speed too.Two single Artemisia ordosica could reduce wind speed at the height of 0.5 m by 59.4% and 19.8%.