模拟雨强和地下裂隙对喀斯特地区坡耕地养分流失的影响  

Effect of simulated rainfall intensities and underground pore fissure degrees on soil nutrient loss from slope farmlands in Karst Region

作　　者：彭旭东[1] 戴全厚[1] 李昌兰[1] 袁应飞 赵龙山[1] Peng Xudong Dai Quanhou Li Changlan Yuan Yingfei Zhao Longshan(College of Forestry, Guizhou University, Guiyang 550025, Chin)

机构地区：[1]贵州大学林学院,贵阳550025

出　　处：《农业工程学报》2017年第2期131-140,共10页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家重点研发计划课题(2016YFC0502604);国家自然科学基金项目(41671275;41461057);贵州省应用基础重大专项(黔科合JZ字[2014]2002)

摘　　要：喀斯特坡面水土地下漏失直接观测难度大,其土壤养分地下漏失的研究仍处于空白,而雨强和地下孔(裂)隙度(以下简称地下裂隙)对其土壤养分流失影响作用尚不清楚。该文以喀斯特坡耕地为研究对象,通过模拟其地表微地貌及地下裂隙构造特征,采用人工模拟降雨试验研究雨强和地下裂隙对喀斯特坡面氮磷钾养分流失的影响。结果表明:雨强对地表产流产沙影响显著(P<0.05),其产流产沙量均随雨强增大而增加,且地表产流产沙临界雨强在30~50 mm/h之间;雨强对地表径流各养分输出负荷、地下径流全氮(TN)输出负荷及径流TN总负荷影响亦显著(P<0.05)。地下裂隙度对地下径流TN输出负荷影响显著(P<0.05),而总体上对其产流产沙、地表径流泥沙各养分输出负荷及总负荷影响不明显。喀斯特坡面TN、全磷(TP)输出负荷总体以径流为主,而全钾(TK)输出负荷则以泥沙为主。雨强是喀斯特坡面土壤养分流失的重要影响因子,地下裂隙度对其养分流失影响不大,但地下径流是喀斯特坡面主要的养分流失方式。研究结果可为喀斯特坡耕地养分流失的机理揭示及源头控制提供基本参数和科学依据。Karst, which is characterized by a double-layer structure of surface and underground spaces, is a landscape formed through dissolution of soluble rocks, including limestone, dolomite and gypsum. Due to interaction of natural factors and human activities, the surface presents rocky desertification landscape with shallow soil layer, discontinuous regolith and even large area bare rocks, meanwhile, the underground space is characterized by sinkholes, closed depressions, subterranean drainage, caves and fissures. Undoubtedly, rainfall intensity acts as a driving force for surface and underground runoff and sediment yield. Underground pore fissure is an important way of soil and water loss on slope in Karst Region. Due to the difficulty in measuring underground leakage of soil and water in the underground space, there is very little study on the underground pore fissure leakage of soil nutrients in Karst Region. Therefore, people＇s understanding on rainfall intensity and underground pore fissure influencing soil nutrients loss is not enough in Karst Region. This paper aimed to study the effect of rainfall intensities and underground pore fissure degrees on nitrogen, phosphorus and potassium loss in runoff and sediment from slope farmland in Karst Region using the method of artificial simulation rainfall experiments. A steel tank（length of 4.0 m× width of 1.5 m× depth of 0.35 m） was built to simulate the surface micro-topography and underground pore fissure characteristics of karst slope in laboratory. Results indicated that： 1） Rainfall intensity had a significant（P〈0.05） impact on surface runoff and sediment yield, and the runoff depth and sediment yield increased with the increase of rainfall intensity. The critical rainfall intensity for yielding surface runoff and sediment changed between 30 mm/h and 50 mm/h. Underground pore fissure degree had no obvious changes with surface and underground runoff and sediment yield. Specifically, soil erosion type on karst slope farmland was a process of transi

关 键 词：养分 产流 产沙 地下裂隙度 雨强 喀斯特坡耕地 

分 类 号：S157.1[农业科学—土壤学] X523[农业科学—农业基础科学]