【摘要】 粮食生产部门是中国农业碳排放的重要来源，在当前“双碳”目标与粮食安全双重压力下，厘清规模经营对要素投入结构与粮食生产碳排放效率的影响，已成为破解中国农业绿色低碳转型难题的关键路径.本文通过厘清规模与效率差异的理论逻辑，基于2023年在中国山东省、江西省、四川省、辽宁省四省开展的1 150份入户调查数据，通过构建广义倾向得分匹配法(GPSM)反事实假设，估计经营规模对粮食生产碳排放效率的平均处理效应，并通过回归调整方法和中介效应模型深入分析了影响机制，明确了要素投入结构在其中的中介作用.研究结果表明，经营规模与碳排放效率呈“U型”非线性关系.优化要素投入结构是保障经营规模对粮食生产碳排放效率产生积极效应的关键.进一步适度扩大农户经营规模将有助于促进我国粮食绿色可持续发展.本文为政府在新发展阶段合理引导规模经营与优化资源配置提供了科学依据，并提出了通过调整要素投入结构来推动粮食绿色生产的政策建议.更多还原

【Abstract】 The grain production sector is a significant contributor to agricultural carbon emissions in China, and under the double pressure of the current ‘dual-carbon’ target and food security, clarifying the impacts of large-scale operation on the factor input structure and the efficiency of carbon emissions from grain production has become a key path to solving the problem of green and low-carbon transformation of China’s agriculture. This study explores the theoretical link between farm size and efficiency disparities, utilizing household survey data collected in 2023 from 1 150 households across Liaoning, Shandong, Sichuan, and Jiangxi provinces. Employing the Generalized Propensity Score Matching(GPSM) method under counterfactual assumptions, the paper estimates the average treatment effect of farm size on carbon emission efficiency in grain production. Additionally, regression adjustment and mediation effect models are employed to analyze underlying mechanisms, highlighting the mediating role of factor input structure. The findings indicate a “U-shaped” nonlinear relationship between farm size and carbon emission efficiency, underscoring the importance of optimizing factor input structure to leverage the positive impacts of farm size on carbon emission efficiency in grain production. Furtherly moderate expansion of farm size will support China’s pursuit of sustainable and green grain production. This research provides a scientific foundation for policymakers to guide rational scale management and resource optimization in the new development era, along with policy recommendations to promote green grain production through adjustments in factor input structure.更多还原