Long‐term land use/cover changes reduce soil erosion in an ionic rare‐earth mineral area of southern China

Abstract

AbstractEcological restoration projects, such as the Grain‐to‐Green Program (GTGP) and the Natural Forest Conservation Program (NFCP), have been implemented to improve vegetation cover since 1998. However, rapid urbanization has caused severe land use/cover (LUC) changes in the Dong River upstream basin. Therefore, it is urgent to study the long‐term (1999–2017) spatial–temporal variation of LUC and soil erosion since the implementation of GTGP and NFCP began in this area. Soil erosion and carbon sequestration were calculated using the revised universal soil loss equation (RUSLE) and C‐fix model. During 1999–2017, forest decreased by 28,857.81 ha and built‐up area increased by 17,193.01 ha. This area experienced severe LUC change, but vegetation cover has been effectively improved. When the observation period was measured in years, vegetation cover had a greater impact on decreasing soil erosion (554.11 × 104 t yr−1) than rainfall, while in months, the impact of rainfall is greater (causing a dramatically rebound of soil erosion in 2014). Furthermore, high‐intensity human activities made soil erosion increased by 37.70% in Yuancheng District, whereas soil organic carbon, total nitrogen, and total phosphorus loss decreased by 49.96, 33.03, and 44.44%, respectively. Moreover, GTGP and NFCP also bring collateral benefits, carbon sequestered by vegetation increased from 99.11 × 106to 124.38 × 106 t CO2, during 1999–2014. And vegetation was the major factor of increased carbon sequestration, rather than temperature or solar radiation. These results elaborate on the impact of LUC changes on spatial–temporal variation of soil erosion. And it can provide a reference for the formulation of soil and water conservation measures in the future.