The regional difference in engineering-control and tillage factors of Chinese Soil Loss Equation

Abstract

Accurate assessment of soil erosion is an important prerequisite for controlling soil erosion. The engineering-control (E) and tillage (T) factors are the keys for Chinese Soil Loss Equation (CSLE) to accurately evaluate water erosion in China. Besides, the E and T factors can reflect the water and soil conservation effects of engineering-control and tillage practices. But in the current full coverage of soil erosion surveys in China (such as soil erosion dynamic monitoring), for the same practice, the E or T factors are assigned the same value across the country. We selected 469 E and T factors data based on runoff plots from 73 publications, and they came from six soil and water conservation regions. Correlation analysis, regression analysis, and nonparametric tests were used to determine the comparability of the data, and it was proved that the runoff plots dimensions are consistent with the local topography. The results of one-way ANOVA and nonparametric tests for E and T factors in different regions showed that the engineering-control practices have good soil and water conservation effects and weaken the regional differences of other environmental factors, so there were no significant differences in E factors between different regions. However, there were significant differences in T factors between different regions, and the geodetector was applied to explore the intrinsic driving force of the spatial distribution of T factors. The results of the geodetector showed that the dominant driving forces of the spatial distribution of different types of tillage practices were not completely the same. When using CSLE to calculate water erosion, the E factor of the same practice can be used uniformly throughout the country, and the T factor needs to be considered and selected according to regional differences. At the same time, when choosing tillage practices in each water and soil conservation region, practices with better sediment reduction benefits should also be selected according to the regional environmental conditions.