Disentangling the influencing factors of spatiotemporal evolution of sloping farmland in the Yangtze River Economic Belt, China

Sloping farmland (SpF) is not only an important space for food production and supply in China's hilly areas, but also a major source of soil erosion. Thus, it is important to achieve a healthy balance between regional food security and environmental protection. Yangtze River Economic Belt (YREB), an important grain production base where SpF concentrated in China, is also faced with serious soil erosion. However, research at the macro scale on the spatiotemporal change of SpF and its driving forces in YREB is still lacking. To bridge the gap, we first analyzed the long-term evolution characteristics of SpF in 1069 counties in the YREB and then explored the driving mechanism of SpF changes during 1980-2020. Results showed that the SpF in the YREB continuously decreased during the study period, with a total area decreasing by 26,300 km2. SpF was primarily concentrated in the upper reaches of the YREB while SpF use dynamic degree varied significantly with the most active change in the lower reaches, reaching to a maximum of 0.324%. The spatial gravity of SpF distribution relocated 20.15 km towards the southwest. As for the driving factors, the socioeconomic factors contributed greater to SpF changes in the whole YREB and its subregions. The intensity of human activities is the most crucial, with factor contribution rate constantly above 0.76. The interactive detection revealed that the prevailing interaction format was primarily bi-enhanced, supplemented with nonlinear-enhanced, which amplified the role of different factors after interacting with them. The pair-wise interaction involving socioeconomic factors had a more potential effect on SpF changes compared to those between physical geography and locational factors. The influence of the intensity of human activities on SpF changes is greatly enhanced after interacting with any factor. It dominated SpF changes in the YREB and its interaction with GDP played an important role at all times. These findings can enlighten differential management strategies of SpF use and ecological conservation in the YREB.