短坡条件下侵蚀产沙与坡长的关系  

Relationship between Soil Erosion and Slope Length on Short Slopes

作　　者：刘和平[1] 王秀颖[1] 刘宝元[1] 

机构地区：[1]北京师范大学地理学与遥感科学学院地表过程与资源生态国家重点实验室,北京100875

出　　处：《水土保持学报》2011年第2期1-5,77,共6页Journal of Soil and Water Conservation

基　　金：国家重点基础研究发展计划项目(2007CB407204);北京师范大学优秀博士学位论文培育基金项目(08022)

摘　　要：采用变雨强人工模拟降雨,选择1~10 m共7个坡长,在5°条件下研究了侵蚀产沙量及其过程与坡长的关系,每个坡长进行干运行和湿运行降雨。结果表明：（1）干运行降雨40~80 min,虽然雨强逐渐减小,但4 m及以上坡长小区的径流含沙量保持较高的水平并出现跳跃,而1 m和2.5 m的小区的径流含沙量在整个降雨过程中较平滑;湿运行含沙量总体上小于干运行,且波动幅度较干运行小。（2）2 h降雨平均含沙量随着坡长的增加而增加,可用二次多项式、幂函数及直线来拟合。（3）侵蚀模数与坡长呈幂函数关系,细沟间和细沟侵蚀模数的坡长指数分别为0.101~0.240和0.757~1.609,表明随着坡长增加,细沟间侵蚀增加较小,而细沟侵蚀增加迅速;干运行的坡长指数均大于湿运行的波长指数。Simulated rainfall of varied intensity was applied on plots of 1~10 m in length and 5 degrees in steepness to investigate the effects of slope length on soil erosion processes and soil loss.For each slope length,a wet run was implemented 24 hours after the dry run.The results indicated that sediment concentration on plots equal or longer than 4 m fluctuated during 40~80 min when the rainfall intensity decreased,while it was much smoother on plots of 1 m and 2.5 m.For wet run,sediment concentration was lower than and did not fluctuate as much as that for dry run.Sediment concentration increased as the slope length increasing,which could be fitted by a quadratic polynomial,power,or linear function.Soil erosion per unit area was related to slope length by power functions,and the exponents of slope length for interrill erosion were 0.101~0.240 and 0.757~1.609 for rill erosion,indicating that rill erosion increased much more than interrill erosion with the increasing slope length.Additional,the slope length exponents for dry run were larger than that of the wet run.

关 键 词：USLE 坡长 含沙量 细沟侵蚀 细沟间侵蚀 

分 类 号：S157.1[农业科学—土壤学]