Spatial pattern and driving factors of cultivated land fragmentation in Jiangsu Province using MGWR model

Cultivated land fragmentation is often considered to reduce agricultural productivity, leading to threatening food security. The pattern and drivers of cultivated land fragmentation can be expected to serve as an important prerequisite for scientific management. Taking Jiangsu Province as the study area, this study aims to assess the cultivated land fragmentation at the county level from four dimensions, including PD (patch density), AWMSI (area-weighted mean shape index), SHDI-S (Shannon's diversity index of area), and COHESION (patch cohesion index). A systematic analysis was made on the clustering features of cultivated land fragmentation in different dimensions using the K-means. MGWR (multiscale geography weighted regression) model was applied to explore the driving factors of cultivated land fragmentation in each county from five dimensions: topographic site, soil properties, urbanization, utilization intensity, and protection strength. The results showed that there were north-south differences in the cultivated land, where the PD and AWMSI were higher in the south than those in the north, the SHDI-S was higher in the north than in the south, and the COHESION was higher in the west. The four dimensions of the county-level cropland fineness index showed three types of clustering: Type A and Type B counties were located in the southern part of the province, both of which shared high patch density, irregular shape, and high area diversity. Among them, the Type A counties were higher connectivity of cultivated land than Type B; Type C counties shared lower patch density, regular shape, low area diversity, and high cropland connectivity, which were distributed mainly in the central and northern parts of the province. In addition, spatial heterogeneity was observed in the driving factors of cultivated land fragmentation in different types of regions. Differentiated fragmentation management should be adopted for the different regions. Among them, cultivated land fragmentation in the southern counties and districts (Type A and Type B) was mainly driven by natural factors (elevation, slope, and soil capacity). There were the more complex factors in the central and northern counties (Type C), including cropland allocation and urbanization. Cultivated land in the Type A counties exhibited a high density and irregular shape of patches, but a high degree of connectivity, which was a greater potential for management. Some considerations were given to promote the merging of adjacent cultivated land for large-scale production when the soil properties were similar in the topographic conditions. A low degree of contiguous cultivated land was observed in Type B counties, indicating the more complex driving factors are more difficult to manage. More attention should be paid to protecting the existing cultivated land for future urbanization. Cultivated land in Type C counties shared a low density and regular shape of patches, with the large cultivated land and continuous distribution. Cultivated land in Type C counties was the most affected by the topographic slope and protection. The central and northern regions were mainly plains with flat terrain and arable land, indicating the low potential for management. However, some attention should still be paid to regulating the use of cultivated land. The finding can provide a strong reference to managing the cultivated land fragmentation in Jiangsu Province. The cropland fine fragmentation model can also be optimized to develop the sustainable use of cropland.