An Empirical Soil Loss Equation

A model was developed for estimating average annual soil loss by water on hillslope for cropland, which is called Chines Soil Loss Equation (CSLE). Six factors causing soil loss were evaluated based on soil loss data collected from experiment stations covering most regions of China and modified to the scale of Chinese unit plot defined. The model uses an empirical multiplicative equation, A=RKLSBET, for predicting interrill erosion from farmland under different soil conservation practices. Rainfall erosivity (R) was the product of rainfall amount and maximum intensity of 10min, and also was estimated by using daily rainfall data. The value of soil erodibility (K), the average soil loss of unit plot per rainfall erosivity, for 6 main soil types was calculated based on the data measured from unit plots and other data modified to the unit plot level. The method of calculating K from soil survey data for regions without measured data was given. The slope length and steepness factors was calculated by using the equations in USLE if slope steepness is less than 11 degree, otherwise the steepness factor was evaluated by using a new seep slope equation based on the analysis of measured soil loss data from steep slope plots within China. According to the soil and water conservation practices in China, the values of bio-control, engineering-control, and tillage factors were estimated.