Identifying the contradiction between the cultivated land fragmentation and the construction land expansion from the perspective of urban-rural differences

Land use contradictions and conflicts between arable and construction land areas have long been major topics in the field of land use research. However, few studies have explored the impact of differences in development between urban and rural areas on the amount and landscape level of arable land. In this study, two decades of data were combined to classify the Yangtze River Delta mega-city cluster area, where urbanization has been evident in China, into urban and rural areas. Based on this, we analyzed the differences in the changes in the amount of arable land caused by the expansion of urban and rural construction land. In this study, a comprehensive framework of arable land fragmentation indicators was constructed and the geographically weighted regression model was introduced to detect spatial and temporal dynamic change patterns of arable land fragmentation caused by different urbanization processes in urban and rural areas. The results show the following: (a) The expansion of urban and rural construction land caused arable land loss, and both contributed non-negligibly to arable land loss. (b) The distribution of the arable land fragmentation index showed obvious spatial heterogeneity, and its low-value area corresponded to a lower level of urban/rural construction land development. However, its high-value area did not show a stable dependence on the level of urban/rural construction land development. (c) Changes in urban and rural built-up land were the driving factors for changes in the degree of arable land fragmentation. In general, the expansion of the urban fringe increased the fragmentation of arable land, and the intensive expansion of urban centers curbed the fragmentation of arable land. However, rural construction land exhibited a stronger and more widespread impact than urban areas as a whole. This study contributes new ideas for arable land conservation policies under the growing mechanization of agriculture, especially in areas with large differences in development between urban and rural areas. Additionally, it emphasizes the need for rational planning of construction land in rural areas. The results of this study can provide references for urban-rural development planning, rural revitalization, and implementation of arable land protection.