The Impact Of Protective Cultivation Measures To Soil Wind Erosion

Wind erosion is one of the reasons for Land degradation in the arid and semi-arid area.And in field of regional soil resource sustainable utilization,agricultural development andfood security, ect., wind erosion is an inportent research content. So, preventing andcontrolling farmland wind erosion effectively have positive practical significance.In order tohave an objective understanding to the characteristics of soil erosion and the impact ofconservation tillage to soil erosion in the arid and semi-arid area, we carried out this study.The main purpose of this study is to seeking more effective method for restraining farmlandwind erosion in the arid and semi-arid area.The test soil was cultivated loessial soils, which sampled from topsoil (0-20cm) of AnsaiCountry, north Shaanxi, during the fallow time of winter. The test crop was wheat. Themeasure data contained total mass of wind erosion,structure of drifting sand1m behind testsection in the vertical height of0~62cm under different wind speed and conservation tillage(stubble,straw coverage,gravel coverage etc.). According to characteristic of natural windspeed of north Shaanxi region, we set4wind speeds (8.0m/s,10.1m/s,12.5m/s and14.3m/s),different stubble height and coverage. Applying comparative analysis to estimate winderosion resistance effect of different conservation tillage. The main results of this study areas follows:(1) Mass of wind erosion had a positive correlation with cover degree. While, differentcoverage treatments had different effect of resisting wind erosion. Straw coverage had moreeffective impact than gravel coverage under the same cover degree. The value of winderosion resistance efficiency changed from26%to42.8%to67.9%with the increasing ofgravel cover degree from30%to60%to90%, While from the part of straw coverage, thevalue of wind erosion resistance efficiency changed from54.6%to72.1%to91.1%. Thewind erosion resistance efficiency of20cm rowledge are more10%than30cm row ledge.(2) The stubble height factor of combined measures had a positive correlation with winderosion resistance efficiency, and coverage factor as well. The impact of change on account ofcombined measure's coverage factor to wind erosion is more weaken than the impact of thesame change on account of single measures, specially in high wind speed,14.3m/s.. (3) The proportion value of collection in0~10cm under the combined measures ofstubble with gravel coverage is lesser than the value under gravel coverage treatment andcontrol group obviously. While in13-62cm, the value of former is greater than the value ofthe latter. Sandstorm flow structure of combined measures of stubble with stubble coverage issimilar to corresponding single stubble coverage,stubble treatment. Sandstorm flow structureof combined measures presents exponential law. Sandstorm flow structure of singletreatments presents exponential law in the upper half, great than exponential law in thebottom half.(4) Impact of single gravel coverage and single straw coverage to wind speed behind testsection, with no sedimentation of soil particles. The stubble height of single stubble treatmentor combined measure's stubble factor higher than the sedimentation presents more obvious,the wind speed gradients reduce more obvious.