玉米季坡耕地地表糙度的变化特征及其对土壤侵蚀的影响

Change of Soil Surface Roughness and Its Effects on Soil Erosion in Sloping Cropland During Maize Growing Season

通过野外模拟降雨试验,研究玉米种植下紫色土坡耕地地表糙度的变化特征,并分析地表糙度对产流产沙的影响。结果表明:随生育时期的推进,地表糙度逐渐衰退,在抽雄期时达到最小,地表糙度平均变幅大小为横坡垄作>顺坡垄作>平作,苗期时变化幅度最小,拔节期或抽雄期时最大;玉米长势越好地表产流时间越晚,各生育时期地表产流时间均为顺坡垄作最早,横坡垄作最晚;全生育期内地表径流量呈现先降低后增高的变化趋势,除苗期外横坡垄作产流量均低于平作,总体而言地表糙度对地表径流的影响未达到显著水平;苗期时土壤侵蚀量随地表糙度的增大呈指数递减,而其余3个生长时期均是随地表糙度的增大土壤侵蚀量呈指数或者幂函数递增。

Based on field artificial rainfall experiments,the change of soil surface roughness on purple soils during the maize growing season was studied,and their effects on runoff and sediment yield were analyzed.The results showed that the soil surface roughness gradually decreased with increasing the growth period.The soil surface roughness reached minimum at tasseling stage and the average change range of surface roughness was cross ridge longitudinal ridge flat planting.The average change range of surface roughness reached minimum at seeding stage and maximum at jointing stage or tasseling stage.The time of producing runoff was the earliest in longitudinal ridge and the latest in cross ridge during each maize growing stage.The total runoff initially increased,and then decreased with the change of growing stages,it was greater in cross ridge than in flat planting besides at seeding stages.In a word,the effect of surface roughness on runoff amount did not reach significant level.Erosion amount was exponential correlation function of surface roughness.Erosion amount decreased with increasing the surface roughness at seeding stage,while it increased with increasing the surface roughness during other periods.