喀斯特典型坡耕地模拟降雨条件下的土壤侵蚀响应  

Response of Soil Erosion in Simulated Condition Rainfall on Typical Slope Farmland in Karst

作　　者：袁应飞 戴全厚[1] 李昌兰[1] 彭旭东[1] 

机构地区：[1]贵州大学林学院,贵阳550025

出　　处：《水土保持学报》2016年第3期24-28,共5页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目(41461057;41061029);贵州省重大专项(黔科合JZ字[2014]2002)

摘　　要：为了定量研究不同降雨强度、坡度和孔（裂）隙度条件下坡耕地土壤侵蚀响应和空间分布特征,采用人工模拟降雨试验,通过模拟喀斯特典型坡耕地耕作层和微地貌特征以及孔裂隙构造特征,研究土壤侵蚀响应和空间分布特征。结果表明：（1）15,30mm/h降雨强度时地表不产流,水土流失形式为地下漏失;50mm/h降雨强度时地表产流产沙,水土流失也以地下漏失为主,地下径流出现最大值。50mm/h以上降雨强度时,土壤侵蚀逐渐向地表侵蚀转变,地表、地下径流泥沙分配呈负相关;（2）在一定条件下,坡度增大,地表径流泥沙量增加,地下径流量减小,当坡度在10°-15°时地表径流泥沙量急剧增加,25°时坡面产流产沙量达到最大值,其中20°坡面径流泥沙与25°接近;地下泥沙与坡度、孔（裂）隙度间变化规律不明显。（3）径流空间分配特征以地下径流为主,其中90 mm/h降雨强度以地表侵蚀为主。（4）降雨强度、坡度和孔（裂）隙度等因子对地表径流及地下径流的影响程度依次为降雨强度〉坡度〉孔（裂）隙度。总之,喀斯特坡耕地以地下漏失为主,地表产流之前随雨强增大而增大,地表径流产生后则反之,极端暴雨（90mm/h）下以地表侵蚀为主;降雨强度对水土流失影响程度最大,其次坡度,再次孔（裂）隙度。In order to study the response of soil erosion and spatial distribution characteristics in different rainfall intensity, different slope and shallow underground crevasse ratio condition. Combined with the artificial rainfall experiments, the response of soil erosion and spatial distribution characteristics were studied by simulating karst typical tillage layer and micro-topography features and crevasse characteristic. The results indicated that： （1）Soil and water loss manifested as underground leakage at 15 and 30 mm/h rainfall intensity, slope surface product runoff and sediment at 50 mm/h rainfall intensity. Soil and water loss primarily manifested as underground leakage 50 mm/h or more rainfall intensity, underground leakage was still an im portant part of soil erosion, and gradually shift to surface erosion, with surface runoff increasing, the surface sediment sharp increased; surface and subsurface runoff and sediment distribution was negatively correlated. （2） Surface runoff and sediment increased and underground runoff decreased with slope magnification, surface runoff and sediment had a sharp increase in 10°-15°. Subsurface slope runoff and sediment reached maximum at 25°, runoff and sediment was close between 20° and 25°. The variation between the crevasse ratio and the underground sediment and slope was not obvious. （3） Underground runoff and sediment was the main space distribution characteristics of runoff and sediment runoff, surface erosion was main at 90 mm/h rainfall intensity. （4）The influencing degree＇s order of factors to surface and underground runoff and sediment was rainfall intensity）slope）crevasse ratios. In summary, underground leakage was main of slope farmland in Karst, it increased with the rainfall intensity stronger before surface runoff product. Conversely after surface runoff product. Surface erosion became main in extreme rain intensity condition. The effect of rainfall intensity on soil erosion was maximum, followed by slope, and crevasse ratios again

关 键 词：模拟降雨 喀斯特坡耕地 孔(裂)隙度 土壤侵蚀 地下漏失 

分 类 号：S157.1[农业科学—土壤学]