摘要
细沟侵蚀是坡面土壤侵蚀的主要形式之一,是介于片状侵蚀与沟道侵蚀之间的一种侵蚀类型,细沟一旦发生,坡面侵蚀量将成倍增加。由于细沟侵蚀的发生需要一定的坡长来汇集径流,对于某一坡度的地块,一次暴雨中细沟总是表现在一定的坡长处发生,这一坡长称为细沟发生的临界坡长。在细沟发生的临界坡长处采取措施控制细沟的发生将大大降低坡耕地水土流失量。通过人工降雨试验发现:细沟发生过程分为片蚀为主阶段、跌坎发育阶段、细沟侵蚀为主阶段和雨后径流侵蚀阶段,紫色土坡耕地细沟的发生以坡面跌坎的贯穿为标志;10°、15°、20°、25°坡耕地细沟发生的平均临界坡长分别为6.25,4.19,2.77,1.60 m;细沟发生临界坡长与坡度呈二次抛物线关系。在人工降雨试验基础上,总结了以控制细沟发生为核心的"大横坡+小顺坡"耕作模式,通过构建横坡截流沟分割地块,实施有效的拦截径流,减少坡面侵蚀泥沙。
Rill erosion is one of the main formats in slope erosion,of which is one special erosion style between sheet erosion and gully erosion.The rate of soil erosion would be double increased,once rill erosion took place.There is a critical length about one vested slope because the rill erosion occurrence needs a certain length to influx runoff.If there were some measures to cut the length of slope,for avoiding rill erosion occurrence the amount of soil erosion would be decreased significantly.According to the artificial rainfall measures,the result displayed that the drop sill was run through means rill occurrence,and there was an abrupt change about the sediment concentration of runoff when the rill took place.There was a relationship of quadratic parabola between critical slope length of rill and slope grade,and the mean critical slope length on purple cultivated land of slope gradient 10°,15°,20°,25° were 6.25 m,4.19 m,2.77 m and 1.60 m,respectively.For the sake of avoiding rill occurrence,we designed a new cultivation mode,named ＇big cross slope and small along slope＇,which was to cut the slope length by ridge and hedgerow for decreasing sediment and reducing slope gradient through long time scale nature erosion.
出处
《水土保持研究》
CSCD
北大核心
2010年第6期1-4,共4页
Research of Soil and Water Conservation
基金
国家科技支撑计划项目2008BAD98B01
2008BAD98B02)
关键词
细沟
临界坡长
紫色土
坡耕地
rill
critical slope length
purple soil
cultivated land
