长江上游紫色土坡耕地水土流失特征及其防治对策

 紫色土是长江上游最重要的土地资源之一,严重的水土流失引发了一系列问题。在对紫色土坡面产流特征进行分析的基础上,研究紫色土坡面产流特征对水土流失的作用机制以及紫色土坡耕地水土流失防治对策。结果表明:紫色土坡耕地产流模式以蓄满产流为主,壤中流在坡面径流总量中所占比例较大;紫色土坡耕地土壤侵蚀导致土壤粗骨沙化,土壤养分流失途径与营养元素的溶解性有关,易溶的N、K主要以溶解态流失,易被土壤固定的P主要随土壤颗粒流失;壤中流是紫色土坡耕地水土流失的重要外营力之一,进行水土流失治理必须对其加以干预。提出长江上游紫色土坡耕地水土流失治理策略与"增渗防冲、排水保土,先排后蓄、蓄以为用"的治理措施。

Characteristics of soil and water loss on purple slope farmland and its control in upper reaches of the Yangtze River

Purple soil is one of the most important land resources in upper reaches of the Yangtze River,however,the severe soil and water loss caused a series of problems.The paper analyzed the runoff characteristics of purple soil in a hill-slope,studied the mechanisms of runoff acts on soil loss,and brought out solutions to prevent soil and water loss on purple slope farmland.The results showed that,stored-full runoff was the main pattern of runoff yield in slope farmland of purple soil,and interflow accounted for a larger percentage of total runoff.Soil erosion on purple slope farmland resulted in soil coarseness and nutrition loss in this specific area,the nutrient loss approaches were related to the solubility of nutrient elements,for instence,N and K were chiefly lost in dissolved state,while P was mainly lost with soil particles.Interflow is an important exogenetic force which causes soil and water loss in slope farmland of purple soil,and it should be controlled for soil and water conservation.According to the characteristics of soil and water loss in this specific area,managements must be carried out,and strategies of the managements includes ＂increasing infiltration,conserving from erosion;draining water,keeping soil;impounding after draining for utilization＂.