Building agricultural sustainability in the population-land nexus: evidence from China

The pressures of aging populations and land degradation together present a unique challenge to enhancing agricultural sustainability. This study moves beyond traditional single-method or static analytical frameworks by innovatively developing a multidimensional assessment model that integrates system dynamics, energy value analysis, and a composite landscape index. By incorporating the dynamic feedback processes among population structure evolution, land-use patterns, and agricultural production systems into a unified analytical framework, the primary objective of this study is to develop a context-sensitive and operational place-based solution matrix. Using China as a case study, our analysis indicates that the threat posed by population aging to agricultural labor and capital intensification is expected to peak between 2030 and 2045. In the baseline scenario, agricultural labor intensity in China is projected to decline by approximately 62.7%, while agricultural capital intensity is expected to rise by 12.76% by 2050. Additionally, the fragmentation of cropland in China has increased from 0.45 in 2006 to 0.58 in 2020, but with the acceleration of rural-urban migration, a positive trend toward land consolidation may emerge around 2040. Overall, by explicitly linking demographic transition, land-system evolution, and productivity assessment, the proposed framework provides a novel and integrative analytical tool for both researchers and policymakers. The results suggest that an integrated development policy based on the population-land nexus is critical to advancing agricultural sustainability.