Spatio-temporal variation in soil erosion on sloping farmland based on the integrated valuation of ecosystem services and trade-offs model: A case study of Chongqing, southwest China

Abstract

Mastering the spatio-temporal evolution of soil erosion on regional sloping farmland is crucial for optimizing erosion control planning and carrying out soil quality evaluations. To simulate the potential or net soil erosion on sloping farmland in Chongqing, China, this study analyzed the temporal and spatial variation features of soil erosion using the integrated valuation of ecosystem services and trade-offs (InVEST) model and other models. The InVEST model was applied to calculate the soil erosion modulus on sloping farmland, hotspot analysis was used to identify hot and cold spots of sloping farmland erosion, and the chord diagram visualization model was used to reflect the transformation quantity and flow direction relationship between different erosion levels of sloping farmland transfer processes in different periods. The results showed that soil erosion on sloping farmland in Chongqing presents a distribution pattern of high values of soil erosion in the northeast and low values in the southwest. Very strong and severe erosion is concentrated in the low mountainous hilly areas in the northeast and southeast of Chongqing, while slightly and lightly eroded areas are distributed in the western and central flatter areas. The soil erosion grade of most sloping farmland is light and middle; in addition, the annual average soil erosion modulus shows a decreasing trend. Only in 2000 was it in the middle erosion grade. The areas with strong, very strong and severe erosion showed a downward trend, with the proportion decreasing from 18 % to 11 %. The average erosion modulus with slope > 25° was the largest (7553 t·km−2·a-1) and presented strong erosion. Soil erosion in sloping farmland mainly occurs between 400 and 1600 m of elevation. This research can effectively improve soil erosion control and quality control of sloping farmland and provide a reference for the sustainable development of land use in the region.