鲁中山区小流域坡面土壤侵蚀的磁性示踪法研究

Use of Magnetic Tracers to Study Soil Erosion Process of Small Watershed in Lu-Zhong Mountain Area

在木质径流小区布设人工磁性示踪剂,利用模拟降雨和自然降雨研究了连续降雨条件下的鲁中山区小流域坡面侵蚀形态的演变以及径流小区侵蚀泥沙量与坡面磁化率变化值的相关性。结果表明,坡面侵蚀方式以溅蚀、面蚀和细沟侵蚀为主。坡面顶部以溅蚀为主,为净侵蚀区;细沟侵蚀在坡面中下部最先发育,试验结束时细沟侵蚀部位已上溯至坡面中上部;坡脚处为侵蚀、沉积的交汇处。坡面的侵蚀程度以细沟发生部位最严重,坡面顶部其次,坡脚处最轻。在模拟降雨和自然降雨条件下,侵蚀泥沙量与坡面磁化率降幅完全吻合,呈极显著性相关,R2分别为0.851 4和0.832 0。因此,磁性示踪法可以准确的监测坡面的侵蚀沉积状况。

By placing magnetic tracers across slopes in the wooden runoff plots,the erosion process of small watershed in Lu-Zhong mountain area and the correlation between the amount of sediments and the variation of magnetic susceptibility,were studied under continuous rainfall of simulated and natural.The results indicated that the main erosion forms included splash erosion,interrill erosion and rill erosion.The splash erosion was the main erosion form of the top,where was the net erosion area of wooden runoff plots.The rill erosion was developed firstly in the middle and lower parts of plots,and then it moved to the middle and upper parts of the plots.The erosion and deposition was occurred at the same time on the foot of plots.So the erosion intensity was slight on the plot foot,serious on the plot top and most serious in the area where the rill erosion occurred.The correlations between the amount of sediments and the extent of magnetic susceptibility reduced were significantly related under continuous rainfall of simulated and natural,whose R2 were 0.851 4 and 0.832 0,respectively.Therefore,the magnetic tracer technology could accurately monitor the erosion process of slope.