Response of rainfall erosivity to changes in extreme precipitation in the Poyang Lake basin, China

Abstract

Soil erosion by water is a serious ecological and environmental problem worldwide. Rainfall erosivity (RE), as well as its relationship to rainfall amount (erosivity density [ED]), is one of the most important factors influencing soil erosion as it measures the capability of rainfall to erode soils. Improving knowledge of the changing characteristics of RE and ED and their response to extreme precipitation is critical for risk assessment of soil erosion and for agricultural management. This study extended previous studies at the basin scale and investigated the temporal and spatial patterns of RE and ED in the Poyang Lake basin, China, and focused on their response to changes in extreme precipitation from 1960 to 2012. The results showed that nearly 80% of the annual RE was concentrated in summer and spring, and the highest ED also occurred during the same period. Summer was the most vulnerable season for potential soil erosion in the Poyang Lake basin. This was principally associated with the characteristics of precipitation in the different seasons. A trend analysis showed clear long-term positive changes in seasonal RE and ED during the study period. The risk of soil erosion in terms of RE and ED in the basin became increasingly higher than before. Spatially, the large RE and ED values were mainly found in the northeast of the basin. These trends and spatial patterns of RE and ED were primarily attributed to the intensification of extreme precipitation in the northeast of the Poyang Lake basin. These findings indicated that considering the strong role of extreme precipitation is essential for the soil erosion control, land management, and agricultural production in the Poyang Lake basin, as well as in other areas.