【摘要】 地形因子在坡耕地土壤侵蚀过程中起着重要作用,重庆市紫色土坡耕地的地形具有坡度陡、坡长短的特点。该文采用野外人工模拟降雨方法研究了不同地形因子条件下紫色土坡耕地的产流产沙特征,结果表明:(1)径流输沙率过程与雨强变化表现为具有一定相关性和一致性的动态响应过程,随着坡长增加,产流量增加很快,4m坡长的产流量约为2m坡长的2.7倍;在20.6°坡度以下,随着小区坡度增大,产流量以接近直线的关系增长,在20.6°时产流量增加到最大。(2)相同坡长小区不同降雨条件下的产沙量存在一定波动性,相同坡度和降雨下4m坡长小区的产沙量约为2m小区的1.3倍,经推导,4m坡长坡耕地径流输沙率大致为2m坡长的0.48倍。(3)在相同坡长条件下,坡度与土壤流失量可拟合为二次多项式关系,紫色土坡耕地土壤侵蚀的临界坡度约为22°。研究成果可为重庆市三峡库区坡耕地水土流失量预测和坡耕地综合整治提供参数和依据。更多还原

【Abstract】 Topographical factors play an important role in the process of soil erosion.The landform is mainly hilly terrain in Chongqing Three Gorges reservoir area which distributed large number of purple soil slope land.This sloping land has feature with steep slope and short slope length.Using the field of artificial rainfall and taking the object of purple soil of sloping land in Chongqing Three Gorges reservoir area,this paper study no the characteristics of runoff and sediment during various topographical conditions.The results showed that:(1)The process of runoff sediment transport rate curve and the rainfall intensity curve has the same fluctuations in the trend.With the slope length increases,runoff increases rapidly,and the runoff in 4 m slope length is roughly 2.7 times the length of slope 2 m.Under 20.6° gradient,with the slope increases,runoff increases close to a straight-line relationship between the slop.In 20.6° the flow rate increased to maximum capacity.(2) The same length of slope plots has a certain amount of sediment yield fluctuations under different rainfall conditions.The sediment yield of 4 m length slope is about 1.3 times comparing with the 2 m length slop.Integrated slope derived,4 m long sandy runoff rate is 0.48 times the slope length 2 m.(3)In different conditions of slope length,the relationship between slop gradient and intensity of soil loss will be fit for the quadratic relationship.The critical slope gradient of erosion in purple soil of arable land is 22°.The results provide the basis for prediction soil erosion and parameters,and the comprehensive improvement of sloping land in the Three Gorges reservoir area of Chongqing.更多还原