Sustainable Grain Production in China: Spatiotemporal Evolution, Regional Disparities, and Spatial Spillover Effects

Achieving sustainable grain production requires balancing production capacity with resource conservation, environmental protection, and long-term food-security functions. This study evaluates sustainable grain production across 30 Chinese provincial-level regions from 2011 to 2022 using a 19-indicator entropy-weighted index. Spatial autocorrelation and regional inequality are examined, and a Spatial Durbin Model (SDM) is employed to identify the local and cross-regional effects of key agricultural factors. The main findings are as follows: (1) Sustainable grain production increased substantially during the study period, although provincial trajectories remained heterogeneous and overall spatial dependence weakened after the mid-2010s. (2) Regional inequality remained persistent. The average Dagum Gini coefficient was 0.1959, and net inter-regional disparities accounted for 54.48% of total inequality; meanwhile, the dominant pairwise disparity shifted from Western–Northeastern China in the early period to Eastern–Western China by 2022. (3) Agricultural mechanization generated significant positive direct and indirect effects, whereas road length exhibited negative direct and spillover effects under the baseline contiguity specification. Agricultural output showed a negative direct association, while the opposing direct and indirect effects of arable land largely offset each other; fiscal support was statistically insignificant. (4) Regional heterogeneity and robustness tests indicate that some spatial effects vary with regional conditions and the definition of spatial connectivity. These findings point to three policy priorities: region-specific development strategies; stronger cross-regional coordination in technology diffusion and machinery services; and infrastructure and resource policies that explicitly account for spatial spillovers.