To explore wind erosion law of farmland and effects of planting spring wheat and pasture on soil and nutrient loss, the experiment took bare land (CK), planting Triticum aestivum and Medicago sativa/Bromus inermis farmland as research objects. We measured indexes of vegetation characteristics, soil wind erosion, and physical and chemical properties. The results showed that soil loss showed a 'U' curve pattern, with more loss in late autumn and early winter, less loss in winter, and significantly increased loss in spring. There were two peak periods of wind erosion (September to November and March to May) from September to June of the following year. The average annual soil loss of bare land was up to 1.7 kg/m², that was, as 1.3 mm thick topsoil was blown away by wind, resulting in the loss of land organic matter up to 236.2 kg/hm². When wheat and pasture were planted, the soil mass loss reduced by 20.1% and 52.3%, and the organic matter loss reduced by 12.2% and 50.7% under the influence of surface vegetation (stubble). Due to the higher coverage, height, and surface biomass of pasture vegetation (stubble) than those of wheat in wind erosion season, the surface roughness, humidity, and water content of topsoil (0-5 cm) of grassland were higher than those of wheat field, resulting in less soil and organic matter loss than that of wheat field. Correlation analysis showed that there were a significant positive correlation between vegetation characteristics and surface roughness and soil moisture content, while there were a significant negative correlation between vegetation characteristics and surface soil and organic matter loss. Regression analysis showed that every 1% increase of vegetation coverage would reduce topsoil and organic matter loss by 4.1 g/m²and 59.3 mg/m². Every 1 g/m² increase of surface biomass would reduce topsoil and organic matter loss by 2.3 g/m² and 34.0 mg/m². The amount of topsoil loss of wheat fields sowed in spring was the same as that of bare land, while planting perennial legume-grass mixtures could significantly reduce the loss of topsoil and organic matter. On the whole, crops sowed in spring in irrigated areas of Gansu would likely cause soil degradation, while planting perennial legume-grass mixtures could fulfill the farmland ecological conservation, improve quality of cultivated land and regional environment.