Study on spatial-temporal process of soil loss on loess slope surface by rare earth element tracers technology

By placing different rare earth elements (REE) in different soil depth and different section across one slope in an indoor plot,one simulated rainfall was applied to study the spatial-temporal process both of depth and section erosion across one slope plot simultaneously.The results indicated that the REE tracer technology has high precision to quantify the spatial-temporal process of soil erosion; In earlier rainfall course,the development degree of sheet and rill erosion was general equation; Otherwise in the following course,the rill erosion was dominant in the total erosion,its average erosion acceleration and the average erosion rate was 15 and 9 times of sheet erosion,respectively; In the end of experiment,the rill erosion took up 90% of total erosion amount; The section of slope bottom occupying about 1/3 slope area was active erosion segment in this experiment.