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Rapid urbanization in China has challenged the sustainability of agroecosystems. Enhancing cropland ecological efficiency (CEE), by achieving higher agricultural productivity with lower environmental costs, is critical for achieving sustainable development goals (SDGs). However, the effects of urban agglomeration on CEE remain unclear, particularly under rapid urbanization. In this study, we developed an assessment framework for CEE that integrates key agroecosystem services, including carbon sequestration, soil conservation, and water retention. The Super-SBM and Spatial Durbin models were employed to quantify the direct and spillover effects of urban agglomeration on CEE, using China's Sichuan–Chongqing urban agglomeration as a case study. The results show that CEE within the studied urban agglomeration first increased from 0.57 in 2000 to 0.76 in 2016 but decreased to 0.72 in 2020 due to resource mismatches. The efficiencies of core cities are generally higher than those of neighboring cities. The results of the Spatial Durbin Model indicate that urban agglomeration have stronger spatial spillover effects than direct effects on CEE. Urban agglomeration initially enhances the CEE of neighboring cities through technology diffusion but suppresses it owing to resource competition after reaching a threshold. These findings underscore the need for tiered urbanization strategies, regional interaction, optimization of agricultural resources, and technological diffusion to reconcile agglomeration benefits with agroecosystem conservation.
Hou et al. (Fri,) studied this question.