Abstract: Based on 2013 cropland data and 2023 land use data from Qiannan Prefecture, the spatial distribution characteristics of “non-grain conversion” of cropland were analyzed using the land use transition matrix. A computational model was established to quantify the cropland non-grain conversion rate, and the driving effects of five factors, including cropland slope, quality, distance to roads, distance to settlements, and distance to water sources, were systematically investigated. The results showed that the non-grain conversion area of cropland in Qiannan Prefecture from 2013 to 2023 was 167 210.34 hm², and the non-grain conversion rate was 31.89%. The “non-grain conversion” of cropland was dominated by the transformation of cropland to forest land and orchards,which accounted for 98.52% of the total “non-grain conversion” of cropland area. The non-grain conversion rate exhibited a significant positive correlation with declining cropland quality, increasing slope steepness, and greater distances to roads, settlements, and water sources. The influence weights of these five factors on “non-grain conversion” of cropland were 0.31, 0.25, 0.19, 0.15, and 0.10, respectively. Among them, the influence weights of natural condition factors (cropland quality and slope steepness) on “non-grain conversion” of cropland reached 0.56.

Key words: “non-grain conversion” of cropland, spatial distribution, driving factor, Karst mountainous area, Qiannan Prefecture