重庆南平镇岩溶槽谷区不同土地利用类型地表水土流失

研究岩溶区水土流失特征有助于更好地开展岩溶地区水土保持，防止石漠化。通过在岩溶区不同土地利用类型布设9个径流场，利用2008-01－2010-08野外雨季的监测资料，得到岩溶区地表水土流失特征。结果表明：速效钾在土壤中易被淋失，磷富集度平均值最低，全氮、水解氮、有机质富集度的平均含量居中。从土地利用类型来看，富集度表现明显的是坡耕地（自然坡耕地强于移土培肥坡耕地），其次是林地，金银花地和草地富集度最低。根据相关系数可知淤泥养分含量与降雨强度呈极显著相关关系，淤泥养分含量与降雨量成正相关，但是相关性差。淤泥养分流失总量是通过泥沙量与淤泥养分含量来共同体现的。土壤侵蚀模数从大到小的顺序依次为自然坡耕地>移土培肥坡耕地>草地>金银花地 >林地。岩溶区并不是每场降雨都要产生径流，主要是大雨尤其是暴雨才生产径流。岩溶区水土流失径流系数平均值在2.31%～14.72%。该研究有助于更好地理解岩溶区水土流失特征，为治理岩溶区水土流失提供科学依据。

Characteristics of surface soil erosion of karst valley in different land use types at Nanping in Chongqing

The research on the characteristics of soil erosion in karst regions was carried out in order to prevent soil erosion better and prevent from rocky desertification. The characteristics of surface soil erosion in karst areas were obtained through nine runoff plots monitoring from January, 2008 to August, 2010. The conclusions were as follows: the enrichment of soil nutrients displayed differently: available K was the highest, total phosphorus was the lowest, and total nitrogen, hydrolysable nitrogen and organic matter were between them. Enrichment levels of soil nutrients in different land use types were different: Sloping land was the most significant (natural slope farmland had stronger enrichment than that of farmland moving soil to build up fertility), followed by woodland, honeysuckle, and grass land. The correlation between the nutrient content and the rain intensity was significant and the correlation between the nutrient outflow and the rain flow was positive but weak. The total loss of soil nutrients was closely related to rainfall and its intensity as well. The modulus of soil erosion reflected differently in different land use types: the slope farming>the honey suckles>the lawn>the forest land. Runoff in karst regions took place only when big rain especially rainstorm occurred, which runoff coefficient was about 2.31%-14.72%. The characteristics of soil erosion can provide scientific basis for preventing soil erosion.