南方花岗岩红壤区不同土地利用类型坡地产流与侵蚀产沙研究

基于自然坡面径流小区,分析了南方花岗岩红壤区5种典型土地利用下坡面地表径流与侵蚀产沙规律.结果表明,不同地类地表径流与侵蚀产沙分异规律明显.裸露荒地、坡耕地、早地和疏林地的地表径流分别是典型林分林地的1 354.9%,1 099.9%,712.3%和285.4%;不同地类土壤侵蚀强度排序为裸露荒地＞坡耕地＞旱地＞疏林地＞典型林分林地,说明植被能较好地调蓄地表径流和减少侵蚀产沙.在不同降雨强度和雨型条件下,不同土地利用的坡面产流与侵蚀产沙也表现出显著的差异.裸露荒地、坡耕地、旱地、疏林地是研究区主要的侵蚀产沙地类.基于径流小区次降雨条件下径流和侵蚀产沙观测资料,建立了不同地类坡面径流与侵蚀产沙的回归方程.

Runoff ,Soil Erosion and Sediment Yield on Sloping Land of Red Soils Derived from Granite on Slopes with Different Landuses in South China

Processes of runoff,soil erosion,and sediment are studied on five runoff plots with different landuse types.Results indicate that the differentiation of the processes is distinct.Runoff on bare wasteland,sloping farmland,dry land,and sparse forest is 13.55,10.99,7.12,and 2.85 times of those on woodland,respectively.In terms of soil erosion modulus,landuse types rank in the descendant order of bare wasteland(7 744.2 t/km²),sloping farmland(3 826 t/km²),dry land(942.2 t/km²),sparse forest(336.5 t/km²),and woodland(10.2 t/km²).Runoff can be stored up and soil erosion can be decreased effectively with the cover of vegetation.Results also show that surface runoff and soil erosion under different landuse types are obviously different for different grades and types of rainfall intensity.Bare wasteland,sloping farmland,dry land,and sparse forest are the main landuse types contributing to soil and water loss.Lastly,based on the single rainfall,regressive models for runoff,soil erosion,and sediment are constructed,their multi-correlation coefficients are found to be significant,and the models can be used for prediction.