Wind-breaking Effect of Various Conservation Tillage Measures during Fallow Period of Cropland
农田休闲期不同保护性耕作措施的防风效应研究

Conservation tillage is essential for soil wind erosion control in the semi-arid area, whereas more studies are needed on the mechanism of different conservation tillage measures to prevent wind erosion. Through field test, we observed wind profiles of 0 to 4 m under seven kinds of conservation tillage, i.e. subsoil tillage, shallow ploughing, stalk mulch after ploughing, no till with tall rape stubbles, no till with short rape stubbles, no till with tall wheat stubbles, no till with short wheat stubbles, and conventional tillage and pasture for comparison. Five items of aerodynamic roughness, friction velocity, and absolute and relative fluctuation intensity of wind velocity were analyzed comparatively on all the underlying surfaces. The results indicated that remnant stubble could reduce soil erosion by reducing near surface wind shear stress. In addition, the height, density and perpendicularity of remnant stubble, straws and grass had influence on aerodynamic roughness and wind velocity fluctuation on different underlying surfaces.