1.State Key Laboratory of Earth Surface Processes and Resource Ecology,Beijing Normal University,100875,Beijing, China; 2.School of Geography, Beijing Normal University,100875,Beijing, China; 3.Rongfeng Holding Grop Co. , Ltd,100070,Beijing, China
Soil erodibility reflects the vulnerability or susceptibility of soil to erosion and is frequently used in the evaluation of soil erosion and the prediction of soil loss. A feasible and reliable method for soil erodibility measurement and estimation is critically required in the research of soil erosion. The objectives of the current study were to estimate the erodibilities of five typical soils in China using micro-plots and to compare the results with those obtained with the traditional unit plot method. Each of the five soils, i. e. , purple soil, black soil, red soil, cinnamon soil and loess soil, was packed into a 20m×2.1m unit plot and a 1m×1m micro-plot, with continuously in a clean-tilled fallow condition and tillage performed upslope and downslope. Runoff and sediment yield were measured for the unit plots in 61 natural rainfall events during the years 2006—2011 and for the micro-plots in 47 events during 2007—2011. Annual soil erodibilities of each soil were calculated as the K values in the Chinese Soil Loss Equation ( CSLE) for both unit plot and micro-plot. And, the calculated formula of K value was presented as K = A / (R·LS·B·E·T). The results showed that the mean annual K values generated with the micro-plots were all lower than those obtained with the unit plots. However, both plot methods yielded generally the highest K values for the purple and black soils, followed by the red soil, and the lowest values for the cinnamon and loess soils. In addition, significant correlations of annual K value were detected between the two methods for all the soils except for the loess soil, because rills were prone to develop in the unit plot of loess soil but not in the micro-plot due to the short slope length. Significant linear regression equations between two K values, i. e. , obtained with the unit plot and the micro-plot methods, were generated for purple soil, black soil, red soil and cinnamon soil. These findings suggest that micro-plots are applicable in soil erobibility estimation for five typical soils in China except for the loess soil.