喀斯特地区坡面径流对产沙的影响

贵州省关岭县蚂蝗田小流域属典型喀斯特流域，根据小流域2009—2012年6个坡面径流小区的定位观测资料，研究了乔木林（黄花梨）、灌木林（女贞）、撂荒草地三种不同植被类型下坡面径流对产沙的影响。结果表明:三种植被类型的产流次数相同，但产沙次数存在较大差异，表现为荒草地 > 乔木林 > 灌木林；灌木林与乔木林的年均径流量相差不大，荒草地的年均径流量是它们总和的2倍；荒草地的年均产沙量最大，为55.17 t/km²，是灌木林的11倍，乔木林的6倍；乔木林的产流量与产沙量无明显相关关系；灌木林表现出线性关系，拟合方程为y=0.1707x+0.2526，R²值为0.48；荒草地表现为幂函数关系，拟合方程为y=0.3246x^1.2965，R²值为0.64。

Influence of Runoff on Sediment Yield on Slope in Karst Area

Mahuangtian watershed is a typical karst basin in Guanling County of Guizhou Province. According to the observation data of six slope runoff plots from 2009 to 2012 in the small watershed, we’ve studied the effect of runoff on sediment in three different vegetation types, which are arbor forest, shrub forest and abandoned grassland. The main results are as followings. Three vegetation types had the same effect in times of runoff, but sediment yield events were different, the yield of sediment decreased in the order:grassland > arbor land > shrub forest; annual runoff in shrub land and arbor forest land was similar but the annual runoff of grassland was double as the total of former two types. Annual sediment yield of grassland was 55.17 t/km² which is 11 times of sediment yield in the shrub forest, and 6 times of sediment yield in arbor; the runoff and sediment yield showed no significant connection in arbor forest but the linear relationship between runoff and sediment yield was found in shrub forest, the fitting equation is y=0.1707x+0.2526, R² values is 0.48, and power function relationship was found in grassland, the fitting equation is y=0.3246x^1.2965, R² values is 0.64.