摘要
喀斯特地区特殊的地表、地下侵蚀产沙是引发石漠化发生发展的重要物理过程。以喀斯特山地石漠化过程中不同石漠化状况的裸坡面为研究对象,通过模拟其地表微地貌及地下孔(裂)隙构造特征,采用人工模拟降雨试验研究其地表及地下侵蚀产沙特征。结果表明:无石漠化、潜在石漠化和轻度石漠化的裸坡在相同条件下的地表产沙量总体上高于地下产沙量,且10 min降雨时段内地下产沙量在0~100 g之间。不同石漠化强度的裸坡地表、地下侵蚀产沙量均随雨强的增大而增加;小雨强(30~80 mm h^(-1))下,随着石漠化强度加剧其地表越不易发生侵蚀,而石漠化强度达到一定程度时(基岩裸露率40%)土壤流失以地下流失为主;大雨强(150 mm h^(-1))下,地表产沙量及其分配比例随基岩裸露率变化不明显,而地下产沙量则呈先增加后减小的变化且在基岩裸露率为30%时达到最大。不同石漠化强度的裸坡地表产沙量及其分配比例随地下孔(裂)隙度变化不明显,地下产沙量及其分配比例总体上随地下孔(裂)隙度增加而增加;在不同地下孔(裂)隙度下(1%~5%),地表、地下产沙量及其分配比例随基岩裸露率变化(10%~50%)差异较大。研究结果对认识喀斯特地区石漠化发生发展机制、揭示土壤侵蚀特征、防治地表地下水土流失具有重要的理论和现实意义。
【Objective】Karst is a landscape formed through dissolution of soluble rocks,including limestone,dolomite and gypsum and characterized by a double-layer structure of surface and underground spaces. This special double layer space structure is the key factor causing development of rocky desertification in karst regions. The non-uniform surface micro-landforms and unique underground hydrogeology in the karst regions complicates the process of soil erosion. As a result,large tracts of bedrocks pop out of the land discontinuing the soil cover,while fissures,ponors,cavities and underground drainage systems are formed underground through dissolution of carbonatite. As large volumes flow through fissures and ponors into underground rivers,water and soil loss in karst regions exists in two forms,surface loss and underground loss,which obviously differ from that in non-karst regions. Guizhou Province,China is one of the largest areas in the world＇s wet climate zone concentratedly distributed with karst. It has a total of 109,084 km^2 of karst,which accounts for 73% of the total area of the province,moreover,about 17.42% of the karst landforms are developed from a large continuous tract of limestone. Under the interaction of natural factors（rainfall,and geology and relief）and human activities,soil erosion in this region is very severe. In recent years,the unique form of underground soil and water loss in the process of karst rocky desertification has aroused more and more concern,but so far little has been reported on the underground soil erosion in karst areas different in rocky desertification degree,and the studies that have been done failed to illustrate either contribution rates of surface and underground soil losses to the total of the area or driving forces and mechanism of karst rocky desertification in the Karst region. Therefore,this study is oriented to determining and analyzing sediment generating process with surface and underground erosion in bare karst areas during the process of karst rocky deserti
出处
《土壤学报》
CAS
CSCD
北大核心
2016年第5期1237-1248,共12页
Acta Pedologica Sinica
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)资助~~
关键词
喀斯特山地
侵蚀产沙
石漠化程度
基岩裸露率
地下孔(裂)隙度
Karst mountain
Erosional sediment yield
Rocky desertification
Bedrock outcropping rate
Underground porosity（fissure density）
