Spatiotemporal dynamics of preferential occupation of high-quality cropland by construction land expansion in china and its implications for food production potential

Global food security is increasingly challenged by issues such as population growth, cropland decline, and rapid urbanization, among which construction land expansion and its occupation of high-quality cropland have become key drivers affecting food production potential. However, existing studies have largely focused on changes in cropland quantity, with little attention to the selective occupation of high-quality cropland as well as its implications for food security. To mitigate this gap, this study develops an Indicator of the Tendency toward Preferential Occupation of high-quality cropland by construction land expansion (ITPO) based on the China Land Cover Dataset (CLCD) and farmland production potential data, which enables a quantitative assessment of the selective effects of urban expansion on cropland quality structure, hoping to provide new insights into the “land-use + food security” nexus. According to the results, several facts have been identified: (1) cropland occupied by construction land expansion exhibits a clear spatial pattern from eastern coastal regions toward inland areas. From 1985–2020, 85.93% of newly expanded construction land originated from cropland, of which 55.8% was high-quality cropland. Such occupation is primarily concentrated in major urban agglomerations, including the Beijing–Tianjin–Hebei, Yangtze River Delta, Pearl River Delta, and Chengdu–Chongqing regions; (2) preferential occupation shows significant spatial and temporal heterogeneities, with persistent high-intensity clusters in eastern, northeastern, and central China, while western China maintains a relatively high proportion of statistically significant counties, approaching 60% in most periods (approximately 55% during 1991–2000); (3) the spatial center of both Construction Land Occupation of Cropland (CLOC) and ITPO shift westward in the study period, with a more significant displacement observed for ITPO, indicating an increasing westward redistribution of pressure on high-quality cropland; and (4) cumulative losses in food production potential caused by construction land expansion during 1985–2020 are estimated at 4.59 × 10 ¹ ⁰ kg (0.15% of total cropland potential), of which 2.69 × 10 ¹ ⁰ kg (0.09%) was high-quality cropland. Overall, although the relative intensity of preferential occupation of high-quality cropland has declined over time, its absolute loss remains substantial due to higher unit productivity and spatial concentration. By incorporating the cropland quality structure into the analysis, this study advances the understanding of the relationship between construction land expansion and food security, providing quantitative evidence to support differentiated cropland protection and territorial spatial governance strategies.