黄土高原坡耕地水土流失地形分异模拟

Topographic Differentiation Simulation of Soil and Water Loss of Slope Farmland in Loess Plateau

退耕还林还草是目前黄土高原整治生态环境和控制水土流失的主体政策。为使生态退耕政策得到有效落实,本文基于WIN-YIELD软件,以延安燕沟流域为例,利用19972002年延安站的逐日气象数据和燕沟流域地貌、土壤及土地利用等资料,模拟分析了不同地形高程、坡度和坡向条件下坡耕地种植不同作物可能产生的水土流失量及其地形分异特征。结果表明:地形坡度是影响径流和泥沙产生的重要因素,产生径流和泥沙的模拟值随地形坡度的增大而增大,地形坡度15°是坡耕地土壤侵蚀模数的相对质变点;地形高程和坡向对产生径流和泥沙的影响不大。

De-farming and restoring forest are principal policies presently for the improving of eco-environment and the reducing of soil and water loss in the Loess Plateau. In order to provide the foundation for the policies to be usefully put in practice, taking Yangou basin as a case study and using day-by-day meteorological data of Yanan station in 1997 to 2002, it simulated and analyzed the quantitative relation between soil and water loss and topographic condition by tile aid of WIN-YIELD software. The results show that topographic slope gradient has important influence on soil and water loss, the bigger slope gradient and the more soil and water loss, and the slope gradient 15° is a relative threshold of soil erosion modulus, but the influences of topographic height and slope aspect are slight.