Spatiotemporal Changes and the Driving Forces of Sloping Farmland Areas in the Sichuan Region

Sloping farmland is an essential type of the farmland resource in China. In the Sichuan province, livelihood security and social development are particularly sensitive to changes in the sloping farmland, due to the region's large portion of hilly territory and its over-dense population. In this study, we focused on spatiotemporal change of the sloping farmland and its driving forces in the Sichuan province. Sloping farmland areas were extracted from geographic data from digital elevation model (DEM) and land use maps, and the driving forces of the spatiotemporal change were analyzed using a principal component analysis (PCA). The results indicated that, from 2000 to 2015, sloping farmland decreased by 3263 km(2) in the Sichuan province. The area of gently sloping farmland (<10 degrees) decreased dramatically by 1467 km(2), especially in the capital city, Chengdu, and its surrounding areas. However, the steep sloping farmland (>25 degrees) decreased by 302 km(2), and was still the largest portion of total farmland in the area. The PCA analysis indicated that the main driving forces behind the changes were social and economic factors. The influence of agricultural intensification factors, such as the multiple cropping index and sown areas of crops, was relatively weak. Given the decrease in the overall slope cultivated area and the increased portion of moderately steep slope land (10-25 degrees) in the cultivated area, special attention should be paid to the scientific conservation of sloping farmland during rapid social and economic development.