Study on the spatio-temporal evolution and influencing factors of farmland abandonment on a county scale

The protection of farmland resources is related to world food security, as well as the smooth realization of the goals of UN 2030 Agenda for Sustainable Development and China's Rural Revitalization Plan. As the most active region in the global economic development and one of the main grain producing areas, the problem of farmland abandonment in the Yangtze River Delta gradually appears with the rapid development of urbanization. Therefore, based on the interpretation data of remote sensing images and field survey data of three periods in 2000, 2010, and 2018, this study used Moran's I and geographical barycenter model to reveal the spatiotemporal evolution law of farmland abandonment in Pingyang County of the Yangtze River Delta. And then, this study selected 10 indicators covering four categories: geography, proximity, distance, and policy, and used random forest model to reveal the main influencing factors of farmland abandonment in the study area. The results showed that the abandoned farmland increased from 441.58 hm² in 2000 to 5797.40 hm² in 2018. The hot spot and barycenter of land abandonment gradually shifted from the western mountainous areas to the eastern plain areas. Altitude and slope were the main factors affecting the farmland abandonment. The high the altitude and the great the slope, the farmland abandonment in mountainous areas were serious. The proximity factors had a greater impact on the expansion of farmland abandonment from 2000 to 2010, and then the impact weakened. In view of the above analysis, the countermeasures and suggestions for maintaining food security were finally put forward.