Comparison Study On Purple Soil And Loess Soil Erosion Processes At Sloping Cultivated Field

Purple soil is a significant sediment sources in Yangtze River. The research of purple soil erosion processes is not only prompt the recognition of the rule of soil erosion, but also provide an important science data to clarify purple soil erosion.. The paper studied the erosion process of the purple and loess soil on slope under different conditions of gradient and rainfall intensity through artificial simulating rain experiments. The main results were showed as followed:(1) Purple and loess soil have different cause formation, mineral composition and mechanical property, which is the intrinsic cause of the differences in two erosion processes.(2) Under the same experiment conditions, the erosion amount on purple soil and loess soil at slopping cultivated field was increasing with rainfall intensity, the runoff and erosion amount of purple soil was bigger than loess soil, slope degree played the most role in purple soil erosion process(3) Runoff rate and sediment amount of purple soil and loess soil was increasing at the beginning,and then was decreasing with the rising of slope degree. When purple slope achieved 25°, or loess achieved 20°the runoff and sediment amount is the biggest.(4)The rain intensity and slope degree make effect with each other in erosion processes. When slope degree is lower than 15 degree, rain intensity take a significant role, and when slope degree is bigger than 20 degree, rain intensity and slope make the same effect on erosion .(5) The rill erosion is the main origin of the total erosion amount, which is the biggest contribution to the slope erosion, and changed from 12.56 % to 82.67 % about purple soil and from 8.67 % to 88.67 % about loess soil.(6) The Reynolds number and Furrow have the same tendency with the changes of the sediment amount in the erosion processes of purple soil and loess soil...