Spatial effects of the synergistic development between agricultural carbon sequestration and emission reduction and food security across China's grain functional areas.

BACKGROUND: Understanding the spatial effects of the synergistic development between agricultural carbon sequestration and emission reduction (ACSER) and food security (FS) is essential for promoting sustainable and high-quality agrarian development. Based on a constructed indicator system for ACSER and FS, this study measures the Coupling Coordination Degree (CCD) between the two in different grain functional areas of China from 2000 to 2023 using a modified coupling synergy model. Furthermore, a Spatial Durbin Model (SDM) is employed to explore the underlying driving mechanisms and spatial spillover effects of their synergistic relationship. RESULTS: (1) From 2000 to 2023, China's CCD between ACSER and FS exhibited a clear spatial gradient, higher in the north and lower in the south. Specifically, spatial clustering intensified in the main production and production-marketing areas but did not reach statistical significance, while the main marketing regions consistently exhibited a trend of spatial dispersion; (2) The spatial Durbin model analysis reveals that the CCD of ACSER and FS in China exhibits significant spatial spillover effects. Among the influencing factors, CO₂ uptake by major crops emerges as the primary driver of their synergistic development, while a higher proportion of cultivated land and increased pesticide and fertilizer use exert negative effects on both local and neighboring regions. (3)The study of regional heterogeneity shows that the CO₂ absorption of agricultural crops in the main production area promotes synergistic development; the synergistic mechanism of ACSER and FS in the production and marketing areas is more complicated, and resource mismatch is the main factor affecting the coupling and synergism of the two; The total power of agricultural machinery in the main marketing areas has a catalytic effect on the local synergy between ACSER and FS, while transregional transmission exhibits negative spillovers, highlighting resource allocation imbalances. CONCLUSIONS: Therefore, to promote the synergistic development of ACSER and FS, it is necessary to adopt region-specific measures based on spatial differences and to strengthen the synergistic effects among key factors within the agricultural system, to enhance resource allocation efficiency and system resilience.