Study On Rill Erosion Process In Sloping Farmland Of Cinnamon Soil And Brown Soil

As the most serious area of soil erosion,the hilly region of western Liaoning province has been listed as the key control area of soil erosion at the national level.Slope farmland is the main place of soil erosion in this area,besides,rill erosion is the main erosion mode of sloping farmland,therefore,it is necessary to study its erosion process for the prevention and control of soil erosion.According to the topographical conditions and rainfall characteristics,we take three gradients(5°,10°,15°)and three rainfall intensities(40mm/h,60mm/h,80mm/h)on the research of cinnamon soil and brown soil slope rill erosion process.The innovation point of this experiment is to divide the dynamic erosion process of slope into stages,which is beneficial to the detailed study of different aspects of rill erosion.The results show that:(1)With the increase of slope and rain intensity,the important points of each erosion stage appear ahead of time,under the condition of rainfall intensity of 80mm/h and slope gradient of15°,the total time of rill occurrence on slope surface is the shortest.Compared with brown soil,cinnamon soil enters the rill erosion stage in advance,but the time from small step-pools to rill formation is longer than that of brown soil,and part of cinnamon soil slopes do not form rill.(2)The slope,rainfall intensity and the change of slope morphology have some influence on the velocity index.Among the three flow velocity indexes,rill velocity is the largest(0.214m/s-0.313m/s),the slope velocityis the second(0.192m/s-0.241m/s),and the rill-to-rill velocity is the smallest(0.13m/s-0.197m/s).After rill erosion,the increase of rill velocity means that the process of erosion and sediment production is accelerated,which results in more erosion.(3)The larger rainfall intensity,the greater runoff corresponding to two soils,which tends to be stable as a whole,while the cinnamon soil in the sediment content tends to decrease,and the brown soil changes greatly,especially after the rill erosion begins,the sudden change of water and sediment is obvious.The difference of total runoff between two soils was not significant,but the total erosion of brown soil is larger than that of cinnamon soil,and shows a multiple relationship of 1.51-2.33,which indicates that the sediment carried by brown soil slope runoff is strong.The amount of water and sediment erosion caused by rill erosion is more than 4 times that of surface erosion.This paper has 39 figures,7 tables and 83 references.