Economic integration and carbon rebalancing in China’s grain functional zones

Achieving regionally coordinated and sustainable development has become an urgent global priority amid accelerating globalization and intensifying environmental challenges. In China, balancing agricultural carbon emission equity with regional economic integration is essential for addressing environmental justice and promoting low-carbon transformation. This study employs the coupling coordination degree (CCD), space–time geographically weighted regression model (GTWR), and partial least squares structural equation modeling (PLS-SEM) to reveal the multi-stage interactive response mechanisms between agricultural carbon emission equity and regional economic integration across China’s three major grain functional zones, from the perspectives of spatial heterogeneity and temporal non-stationarity. The results indicate that the major grain-producing zones (MGPZs) exhibit high ecological support but low production efficiency, while the major grain-consuming zones (MGCZs) maintain strong economic performance under ecological constraints, and the production-consumption balanced zones (PCBZs) have been fluctuating. There are significant differences in economic integration, with higher integration in MGPZs and MGCZs compared to lagging PCBZs. The coordination between equity and integration shows significant spatial and temporal variations, with only Jiangsu Province achieving high coordination. Moreover, key factors, including agricultural industrial structure, investment intensity, and pesticide application intensity, exert heterogeneous and sometimes conflicting effects on the carbon-economy coordination at different dimensions. These findings suggest that one-size-fits-all policies are inadequate. Instead, region-specific strategies that focus on ecological compensation, efficient input management, and interregional cooperation are essential. The study provides a theoretical basis for environmental impact assessments and the formulation of targeted policies that harmonize agricultural carbon mitigation with sustainable regional economic development.