雨强和土地利用方式对黄土丘陵区水土流失的影响

为了更好掌握黄土丘陵区雨强和土地利用方式对水土流失的影响规律和机理，利用人工降雨模拟器，设计了5种雨强和4种土地利用方式的区组试验，对水土流失进行了定量研究。结果表明：雨强对不同土地利用方式的产流产沙都呈极显著的正效应，4种土地利用方式的地表平均产流产沙与雨强均呈幂函数显著增长趋势；5种雨强的平均地表产流量为林地＞休闲耕地＞栽培草地＞草地，平均产沙量分别为休闲耕地＞栽培草地＞草地＞林地，产流与产沙没有呈现完全的对应关系。如果没有林冠层、灌木层和枯枝落叶层对降雨的截留、阻滞和消弱，林地产流量高于其他土地利用方式，但具有良好的保土效果，而草地具有良好的保水和保土效果。

Effects of rainfall intensity and land use on soil and water loss in loess hilly region

An experimental research on the effects of rainfall intensity and land use on soil and water loss was carried out under simulated rainfall to master the regularity and mechanism in five different rainfall intensities and four land use modes in loess hilly region. The results showed that rainfall intensity was positively correlated with runoff and sediment yields. The function was power between the average surface runoff or sediment and rainfall in four land use modes. The order of average surface runoff yield was forest lands >fallow cultivated lands>cultivated grasslands>grasslands. And the order of sediment yield was fallow cultivated lands>cultivated grasslands>grasslands>forest lands. There was no complete correspondence between runoff and sediment. If there is no intercepting, retarding and reducing of rainfall by canopy, shrub and litter layer, the runoff of forestry is larger than that of other land use patterns. Findings also show that the forestry has a good effect on soil conservation, and the grassland has a good effect on soil and water conservation as well.