为了研究植被对坡面侵蚀输沙的影响机制,采用模拟降雨试验,结合激光扫描方法,分析了不同坡位植被缓冲带下坡面产沙来源的变化特征。结果 表明:没有植被覆盖时,坡面侵蚀最严重的区域位于下坡下部到中部,侵蚀产沙多来源于此。当植被种植于上坡中下部和下部时,坡面产沙主要来源于下坡中下部到中部,且侵蚀发育程度有所降低。随着植被缓冲带种植的位置上移,泥沙和径流的侵蚀和运动具有了更大的范围,坡面侵蚀最严重的区域也逐渐向上扩展,从下坡下部扩展到上坡中部,产沙量达到峰值,侵蚀严重程度增长24%～45%。植被布设于上坡长度60%时,其调控范围可覆盖整个坡面,产沙范围和侵蚀程度与裸坡相比分别降低33%,53%,甚至改变了侵蚀方式,细沟侵蚀已经开始向片蚀转变,具有较好的侵蚀输沙调控作用。研究结果揭示了不同坡位的植被植被缓冲带可以通过影响侵蚀方式来调控坡面侵蚀产沙来源。
In order to study the effect mechanisms of vegetation on erosion and sediment transport, the artificial rainfall simulator and three-dimensional scanning technology were used to investigate the character of sediment sources in different positions of vegetation buffers. The results show that the main source of sediment yield is in section from the middle to the lower part of the downslope area where there is no vegetation, and the most serious erosion distributes in this area; the main region of sediment source is located in the middle lower part of the downslope and the whole downslope as the grass strip is laid in the lower part of the upslope and the middle lower part of the upslope where the erosion is alleviated; when the grass strip moves to the upper part of upslope, runoff flows longer and sediment yield has more sources, the main source area of erosion moves up simultaneously, which even extends from the lower part of the downslope area to the middle part of the upslope; the main erosion range increases by 2～3 times, and the degree of erosion increases by 24%～45%, the erosion sediment yield reaches the peak within the test range; when the planted grass strip occupies 60% of the upslope length, its regulation range can cover the entire slope, effectively controlling the main erosion range and degree are 33% and 53% lower than those of bare slope, respectively, which better controls the mechanism of erosion and sediment transport, more importantly, transforms the main erosion pattern from rill erosion into sheet erosion; the regulation of vegetation on the processes of erosion and sediment transport is realized in the slope. The information indicated that vegetation in different positions of slope can regulate sediment source in a slope by affecting the erosion patterns.
