利用REE示踪法研究坡面侵蚀过程

次降雨条件下坡面侵蚀形态的演变过程和细沟的发生发展过程是土壤侵蚀规律研究中的重点和难点。利用REE示踪法,采取沿坡面垂直分层布设的新的试验方法,通过室内模拟降雨试验,对坡面侵蚀演变过程进行了探索性研究。结果表明:降雨初期坡面侵蚀以面蚀为主,细沟出现后,坡面侵蚀加剧;随着降雨时间的延续,累积面蚀量和细沟侵蚀量逐渐增加,但后者的增加速率大于前者,面蚀占总侵蚀量的比率随降雨时间呈曲线形式逐渐递减,细沟侵蚀则逐渐增加;试验结束时细沟侵蚀量为面蚀量的2～4倍。本研究为定量区分和研究坡面侵蚀过程中面蚀和细沟侵蚀量,面蚀向细沟侵蚀的转变以及细沟侵蚀发生、发育提供了新的思路和解决途径。

Study on erosion process by the REE tracer method

Changes of the erosion type and the rill erosion process under simple rainfall is one of the key problems in soil erosion research. By placing rare earth elements (REE) on different soil depth across the slope, the simulated rainfall is applied to study the change of erosion type and the rill erosion process. The results indicate that the main erosion type is sheet erosion at the beginning of the experiment, and serious erosion happens after the rill erosion appears. Accumulated the sheet erosion amount and rill erosion increase with the rainfall time, and the increase rate of the latter is bigger than of the former. The ratio of sheet erosion to total erosion decrease and the ratio of rill erosion to total erosion increases with the time passing by. At the end of the experiment, the rill erosion amount reaches 2 to 4 times of the sheet erosion. In this paper, a new REE tracer method is proposed to quantitatively distinguish the sheet erosion amount and the rill erosion amount. Also it can be used to study the process from sheet erosion to rill erosion, and it would be a new method to study the erosion process on slope.