Impact of urbanization on the supply- demand matching of multiple cultivated land functions in the Yangtze River Delta region

Cultivated land use has been one of the major challenges to national food security and ecological stability in sustainable agriculture, especially in rapid urbanization and industrialization in recent decades. Current cultivated land is often required to balance between the supply and demand of multiple functions, rather than a single production. This study aims to clarify the impact of urbanization on the supply-demand matching multiple for cultivated land functions (CLFs). Land resource allocation was also optimized for sustainable utilization and coordinated development of modern agriculture. The study area was taken from the Yangtze River Delta (YRD), one of the most economically developed and urbanized regions in China. There were drastic variations in the land use, especially in Shanghai, Jiangsu, Zhejiang, and Anhui, due to rapid urban expansion, indicating the supply and demand of various CLFs. The supply and demand levels of five CLFs (grain production, water conservation, carbon sequestration, habitat quality, and landscape culture) were quantitatively measured from 2000 to 2023 using remote sensing data, statistical yearbooks, and field surveys. The spatial-temporal patterns of supply-demand matching were finally obtained to evaluate the different types of urbanization, such as population, economic, spatial, and social urbanization. The results showed that: (1) Grain supply shared a “higher in the north, lower in the south” pattern in the south in the study period, which was closely related to superior natural conditions in northern Jiangsu and Anhui. While the water supply presented the opposite trend, due to more abundant precipitation. Carbon sequestration showed significant overall growth, which was attributed to ecological and agricultural policies. High-value areas of habitat quality supply were in the YRD’s southwest. Landscape culture high-value areas were in eastern coastal Jiangsu. All CLFs increased with the expansion of city size in Shanghai, southern Jiangsu, and eastern Zhejiang. (2) City size significantly dominated CLF supply-demand matching. Small cities generally shared the surplus supply of various CLFs, while megacities and supercities presented a shortage of supply for various CLFs, as the urban expansion occupied cultivated land for the demand of populations/industries. Shanghai and southern Jiangsu significantly enhanced the urbanization pressure on sustainable cultivated land. (3) Different types of urbanization varied in the heterogeneous impacts. Social urbanization also dominated the supply and demand matching for grain production. There was a tradeoff between the urban population and the rural labor transfer. Economic urbanization shared the greater impact on carbon sequestration and landscape culture than the rest. Spatial and economic urbanization strongly dominated the supply and demand matching for the habitat quality. Importantly, the interactions between urbanization types also dominated the supply-demand matching for the multiple CLFs more than the rest of the single urbanization. This finding can provide the decision-making basis to promote high-quality urbanization and sustainable cultivated land in the YRD region.