金沙江干热河谷地区降雨对水土流失的影响

金沙江干热河谷是长江上游生态环境最脆弱、水土流失最严重的区域之一。在对攀枝花市2010-2012年降雨观测基础上，结合9个径流小区水土流失量的监测数据，剖析金沙江干热河谷地区降雨对水土流失的影响。结果表明，金沙江干热河谷地区6-10月为降雨集中期，6-8月是强降雨集中期，强降雨累计雨量占全年降雨量的31％～36％；水土流失的发生一般为强降雨所致，本地区降雨侵蚀力因子为336.17（J·cm）/（m2·h）；径流系数与降雨强度、坡度、农作物种类、耕作方式有关，坡耕地的径流系数为0.08～0.12，并随坡度的增加而增大；坡改梯径流系数为0.02～0.04，灌木林（黄连翘）为0.02～0.04，鱼鳞坑为0.08，地膜覆盖（顺坡）为0.28。

Influence of the Rainfall on Soil and Water Loss in the Dry-Hot Valleys of the Jinsha River

The dry-hot valleys of the Jinsha River are one of the areas with worst ecological environment and most seriously of soil and water loss as well.Basing on the rainfall data in Panzhihua from 2010 to 2012 and combining with monitor data of water and soil loss about 9 runoff plots of slope farmland,the influence of the rainfall on soil and water loss in the dry-hot valleys of the Jinsha River was analyzed.The results showed that the rain falls mainly occurred from June to October and the strong rainfall which accumulation precipitation account for 31%-36%of the annual total occurred from June to August.The soil and water loss were caused by strong rainfall,the erosive factor of rainfall was 336.17（J·cm）/（m2·h）in this area.The runoff coefficient related to rainfall intensity,gradient,crop species and tillage methods,The runoff coefficient of crops on sloping lands was 0.08-0.12 and increased with the increase of intensity.The runoff coefficient in transforming slope into terrace,shrub forests （Fructus forsythiae）, fish-scale,plastic film mulching along the slope was respectively：0.02-0.04,0.02-0.04,0.08,0.28.