Mechanism And Application Of Crop Stubble On Alleviating Field Wind Erosion In Agriculture And Pasture Ecotone

The wind erosion was serious problem in the agriculture and pasture ecotone of the North foot of Yinshan Mountain. However, it is difficult to quantify and manage wind erosion at field level. This study was carried out in Wuchuan County, Inner Mongolia, where is a typical aeolian region with chestnut soil. The wind erosion in terms of sand accumulation was observed in strip intercropping systems such as silage millet/potato, oat/potato and rape/potato, with various space arrangements. The treatments included the monoculture with bare and tilled soil in winter time, strip intercropping systems with remaining various crop stubble heights and widths of stubbles in the winter time. Field observation, indoor wind tunnel measurements, and outside wind tunnel measurements were conducted to quantify wind erosion from soil surface in different treatments. The relationship between wind erosion amount and intercropping arrangement (e.g. belt width) as well as crop stubble height were analyzed to optimize configuration of strips. The mechanism of reducing wind erosion by field crop stubble in winter time was studied. The agronomy practices for alleviation of wind erosion in potato field was suggested base on the constructing a biological fence with optimal crop stubble height and width. The main results were:1. A new methodology, which is defined as Wind Erosion Cycle based on the principle of weight difference, was used and validated in the field wind erosion measurements. it was verified to be good method to quantify wind erosion in the Aeolian region. It overcomes the limitations of common used methods.2. The sand storm would not happen if the soil water content was more than 7%. The wind erosion sediment distributed exponentially when the wind velocity was lower than 9 m/s, and following a power function cure when wind velocity was higher than 9 m/s. The critical threshold of wind velocity for soil erosion showed a linear relationship with soil moisture content. The relationship between critical threshold of wind velocity for soil erosion, soil physical sand content and the soil moisture content can be expressed by a binary regression. The wind erosion modulus was expressed as a trinary quadric regression. 3. The wind erosion modulus increased exponentially with wind velocity in treatments with crop stubbles. Under same wind speed, the wind erosion modulus decreased as a power function when the strip width was increased. The tillage practice and bare soil in the winter time were main cause of wind erosion. The effect of strip width on reducing amount of wind erosion was significant. However there were no significant effects on wind erosion for crop stubble height and strip width of intercropping systems. The soil wind erosion modulus decreased linearly with crop stubble height. The wind erosion modulus can expressed as a binary regression with the strip width, crop stubble height and wind speed in oat/potato and rape/potato strip intercropping systems.4. The effects on reducing wind erosion by crop stubbles, which are defined as biological fences with parameters of strip width and stubble height, were studied by wind tunnel and field measurements. The study provided a reliable methodology to determine wind erosion in the drought agricultural area. The results were concluded that the cropping pattern of strip intercropping with remaining stubbles at the field during winter time could significantly reduce wind erosion. The results enrich mechanism and practices of wind erosion management in drought area of agriculture and pasture ecotone.