黄土丘陵区土壤侵蚀链垂直带水沙流空间分布

Spatial distribution of runoff and sediment in the vertical belts of soil erosion chain in loess region of hilly and gully

采用多坡段组合模型、人工模拟降雨实验研究了土壤侵蚀链垂直带水沙流空间分布变化特征。结果表明:愈向下坡方向的坡段产流量愈大,单位面积、单位时间的产流量按坡段排列为:谷坡>梁峁坡下部>梁峁坡中部>梁峁坡上部。雨强为29 7mm/h时,坡面上没有沟蚀发育;雨强为60 5mm/h时,细沟主要分布在梁峁坡下部和谷坡处;雨强为90 2mm/h时,各种侵蚀形态在坡面均有较好发育,细沟的出现部位一直伸展到梁峁坡中部和上部之间。由于上坡来水来沙的作用,梁峁坡的产沙量增大了20 2%～63 5%,谷坡的产沙量增大了42 9%～74 5%。

Spatial distribution of runoff and sediment in the vertical belt sections of soil erosion chain is studied by the simulated rainfall examination on block diagram combined with multi-slope sections. The results show that the runoff increase from the upper slope to lower one.The runoff per unit area and the unit time increases in order of the upper hillslope, the middle hillslope, the lower hillslope and the gully slope. Also, different the erosion patterns develop well on the hillslope with rainfall intensity of 90.2 mm/h and rill erosion extends from bottom of the slope to the middle and the upper hillslopes. Rill erosion, in contrast, only occurs in the lower hillslope and gully slope with rainfall intensity of 60.5mm/h, and gully erosion do not develop with rainfall intensity of 29.7mm/h. Due to the effect of runoff from the upper slope, sediment yields of hillslope and gully slope have increased by 20.2%～63.5% and 42.9%～74.5% respectively.