中文摘要：

利用径流小区观测法探讨了坡长对黔西北地区坡面产流产沙的影响。结果表明,（1）坡面产流量随坡长的增加呈先减少后增加再减少的变化趋势,坡面产沙量随坡长的增加而增加,且产沙量与坡长之间呈线性关系。（2）坡面产流量和产沙量均与暴雨存在显著性相关,暴雨条件下坡面产流量占年产流量的35.1%~52.2%,坡面产沙量占年产沙量的67.4%~87.8%。（3）低雨强时,产沙量随坡长的增加无明显变化规律;中、高雨强时,产沙量随坡长的增加而增加,且产沙量与坡长之间的关系可用线性方程表示。（4）不同坡长条件下坡面产流量和产沙量均与降雨复合指数PI60存在较好的幂函数关系。（5）坡面产沙量与坡长、坡面产流量之间存在较好的幂函数关系,其关系式为：M=0.176（LH）1.261。

英文摘要：

Impacts of slope length on runoff and sediment in Northwest Guizhou were studied by means of runoff plots observation.The results showed that（1）runoff generated on slopes showed a trend of decreasing-increasingdecreasing with the increase of slope length.Sediment yield on slopes showed a trend of increase with the increase of slope length.There was a significant linear relationship between sediment yield and slope length.（2）Runoff generated and sediment yield on slopes were significantly correlated with rainstorm,respectively accounting for up to 35.1%~52.2% of the annual runoff and 67.4%~87.8% of the annual sediment.（3）There was no regularity between sediment yield and slope length under light rainfall intensity.Sediment yield increased with the increase of slope length under moderate and heavy rainfall intensity,which could be fitted by linear function.（4）Runoff generated and sediment yield on slopes had power function with factors of PI60.（5）Sediment yield on slopes showed significantly power function relationship with slope length and runoff generated on slopes,which was expressed by M=0.176（LH）1.261.