摘要
通过人工模拟降雨试验,探索表土剥离对喀斯特坡耕地侵蚀产沙的影响。采用钢槽装填土石模拟喀斯特坡地的"二元结构",通过正交试验分析了下垫面类型(坡耕地、裸坡地)、雨强(0.5,0.8,1.3mm/min)和地下孔(裂)隙度(1%,2%,3%,4%,5%)对坡地地下产流、产沙的影响。结果表明:表土剥离导致下垫面土壤物理性质改变,是影响坡地产流、产沙特征变化的主要因素。降雨强度主要影响坡地地下产流量和产沙量,地下孔(裂)隙度主要影响径流和泥沙在地表和地下的分配比例。表土剥离后表层土壤的容重和土壤颗粒分形维数呈显著性增大,导致土壤透水性、孔隙大小等发生改变。相比之下,在0.5mm/min雨强下,裸坡地的地下产流量、产流系数、产沙比重均大于坡耕地,雨强增大至0.8,1.3mm/min后,则是坡耕地大于裸坡地。同时,随着降雨强度的增大,坡耕地产流量和产沙量随雨强的变化顺序为0.5mm/min雨强>0.8mm/min雨强>1.3mm/min雨强。而裸坡地的产流量大小随雨强的变化顺序为0.8mm/min雨强>1.3mm/min雨强>0.5 mm/min雨强,产沙量大小随雨强的变化顺序为0.5 mm/min雨强>0.8mm/min雨强>1.3mm/min雨强。增大地下孔裂隙度能显著(p<0.05)的增大两种坡地的地下产流、产沙的贡献量。地下孔裂隙度为1%~3%条件下,2种坡地地下侵蚀产沙比重存在极显著差异(p<0.01),随着地下孔(裂)隙度增大至4%和5%,两者间的差异缩小。虽然裸坡地的地下侵蚀产沙量小于坡耕地的,但是其地下产沙比重更大。在喀斯特地区进行开发建设时,应注重地下漏失的防治工作。研究成果能够为喀斯特坡地土壤侵蚀研究和水土流失防治提供重要参考。
The impacts of topsoil stripping on soil erosion and sediment yield and their characteristics were analyzed in karst slope by the simulated rainfall experiments. The ＂dualistic structure＂ of karst slope was simulated by a steel tank filled with soil and rock. An orthogonal test was conducted to study the characteristics of underground runoff yield and sediment yield in different underlying surface types （slope farmland, bare slope）, different rainfall intensities （0.5, 0.8, 1.3 mm/min） and different degrees of underground hole （crack） （1%, 2%, 3%, 4%, 5%）. The results showed that the changes of soil surface physical properties caused by topsoil stripping were the imperative affecting factors on the underground runoff and sediment yield variations. Underground runoff and sediment yield in slope farmland were mainly impacted by rainfall intensities, while the distribution ratios of runoff and sediment in the surface and underground were mainly influenced by different degrees of underground hole （crack）. Topsoil stripping resulted in a significant increase in soil bulk density and fractal dimension, which made the soil water permeability, pore size and other soil physical properties change. When the rainfall intensity was 0.5mm/min, the underground runoff yield, runoff coefficient and sediment proportion in the bare slope were greater than those in the slope land, but when the rain intensity increased to 0.8 and 1.3 mm/min, the results were just reverse, the correspond- ing values in slope land were greater than the bare slope. The runoff and sediment yields in slope land with different rainfall intensities dwere 0.5 〉 0.8 〉 1.3 mm/min. However, the runoff yields in bare slope were 0.8 〉1.3 〉 0.5 mm/min, and the sediment yields were 0.5 〉 0.8 〉1.3 mm/min. The increased degree of underground pore fissure had a significantly （p〈0.05） effect on increasing contribution of runoff and sediment yield of slope. Under the degree of underground hole （crack） of 1%-3%, there was a significantly difference （p〈0.01） between the underground erosion proportions in two slopes, but the difference diminished gradually with the degree of underground hole （crack） increasing to 4 % and 5 %. It was worth noting that, although the amount of underground sediment yield of the bare slope was less than that of the slope land, the proportion of underground sediment yield of the bar slope was greater. It should be paid more attention to control the underground leakage where farmland was employed to development and construction in karst area. The results could provide great assistance and reference for further research and controlling water and soil erosion in the Karst region.
作者
严友进
戴全厚
伏文兵
杨智
YAN Youjin1 , DAI Quanhou1 , FU Wengbing1,2 , YANG Zhi1,3(1. Forestry College of Guizhou University, Guiyang 550025; 2. Guizhou Qian Shan Wan Shui Environmental Protection Technology Co. Ltd. , Guiyang 550001; 3. Ouizhou Shengtai Engineering Consulting Co. Ltd. , Guiyang 55000)
出处
《水土保持学报》
CSCD
北大核心
2018年第1期67-73,79,共8页
Journal of Soil and Water Conservation
基金
国家重点研发计划项目(2016YFC0502604)
国家自然科学基金项目(41671275
41461057)
贵州省重大专项(黔科合重大专项字[2016]3022号)
贵州省应用基础重大专项(黔科合JZ字[2014]2002)
关键词
喀斯特坡地
表土剥离
地下漏失
产流产沙
人工降雨
karst slope
topsoil stripping
underground loss
runoff and sediment yield
artificial rainfall
