Reexamination of the Xie model and spatiotemporal variability in rainfall erosivity in mainland China from 1960 to 2018

Abstract

Soil erosion has become one of the most serious global environmental and ecological crises. Rainfall erosivity measures the potential ability of precipitation to trigger soil erosion. This study estimated the degree of rainfall erosivity in mainland China from 1960 to 2018 using the Xie model and analyzed its spatiotemporal variability. The accuracy of the Xie model was reexamined and further verified with the use of data from densely distributed stations by comparing it with two typical daily models and an hourly model. The relationships between changes in rainfall erosivity and soil erosion were also discussed. Results showed that annual rainfall erosivity in mainland China ranged from 2 to 23,129 MJ⋅mm/(hm2⋅h⋅a) and decreased gradually from southeast to northwest. Annual rainfall erosivity also showed a significant increasing trend (P < 0.05) with a mean value of 3738 MJ⋅mm/(hm2⋅h⋅a) and a growth rate of 8 MJ·mm/((hm2·h·a)·a). The significant breakpoint (P < 0.05) occurred in 2002. Multiple oscillation periods were identified, but 3.5 years was identified as the main oscillation period. The Xie model was shown to be more accurate for estimating rainfall erosivity in mainland China because of its simple formula, which reduces computing time and the effort needed to make calculations. Therefore, the Xie model provides a robust daily model that could be widely used in mainland China. Although annual precipitation has reduced, the increasing concentration and intensity of precipitation appears to be the primary reason underlying the increase in rainfall erosivity. Efficient, economic, and environmental measures need to be taken to address some of the challenges of soil conservation in mainland China.