YIN Rumeng, LI Xin, XIAO Yi, WANG Linyan, ZOU Wei
Cultivated land protection policies in China have long been biased toward the supply side, with insufficient attention to changes in residents' dietary demand, leading to deviations in policy effectiveness. Anchored in the concept of “limited” dietary de-mand, where human diets are readily saturated and excessive intake yields no additional benefit, this study took plant-based dietary de-mand as a typical case. Using provinces as the unit of analysis, this study integrated statistical and demographic data, applied GIS-based spatial analysis and statistical tools, and constructed supply-demand ratio indicators for different crops by decomposing their con-tributions. This approach depicted the supply-demand patterns and spatiotemporal evolution of calories, protein, and fat between 2000 and 2022, assessed the balance between food supply and demand, and explored pathways for adjusting food supply-demand structures across regions. The results showed that: ① From 2000 to 2022, China's cultivated land food supply capacity under plant-based dietary demand increased overall, with calorie and protein needs being largely met, but there was a persistent deficit in fat-derived energy sup-ply. ② During the study period, regional disparities in supply-demand ratios under plant-based dietary demand were evident, with calo-ries, protein, and fat exhibiting a spatial pattern characterized by “depressions at the eastern and western ends with central uplift and a north-south gradient with higher values in the north,” and their temporal trajectories remained stable with no marked shifts in spatial form, location, or overall configuration. ③ Between 2000 and 2022, the total supply of calories, protein, and fat from Chinese cultivated land increased significantly. Calories and protein were mainly contributed by maize, vegetables, and wheat, while fat was primarily sup-plied by rapeseed, vegetables, and soybeans, reflecting persistent structural shortcomings. ④ Under a plant-based dietary pattern, the overall demand for cultivated land by residents declined, but different crops exhibited both surpluses and deficits in various regions, showing significant pattern differentiation. This study recommends shifting from “emphasizing supply” to “production according to de-mand and demand-side management,” reasonably guiding plant-based diets, and increasing the consumption of coarse grains (such as cereals and tubers), soy products, rapeseed oil, fresh vegetables, and fruits, among other foods. On the supply side, it is necessary to op-timize planting structure and reasonably allocate cultivated land resources according to local conditions and timing. In terms of gover-nance, improving cross-regional adjustments and horizontal compensation between production and marketing areas would help form a new mechanism for coordinated cultivated land protection and food security.
