粮食生产对生态碳汇的影响研究

目的]协同推进粮食安全与碳中和目标是当下中国的核心议题，但粮食生产对生态碳汇的影响尚不明确，文章尝试梳理粮食生产影响生态碳汇的作用机理，并实证甄别粮食生产影响生态碳汇的净效应。方法]构建粮食生产影响生态碳汇的分析框架，利用2000—2017年中国县域面板数据，采用双向固定效应模型进行实证检验。结果]基准分析表明，粮食生产对生态碳汇总量具有显著正向影响。异质性分析表明，复种指数的适度提升有助于发挥粮食生产的碳汇效应；相较于西部和东北地区，东部和中部地区粮食生产的碳汇效应更大。结论]应重视粮食生产的碳汇属性，通过耕作制度调整等手段加强土壤保护，挖掘粮食生产的碳汇潜力；优化陆地绿色植被空间布局，降低农地、林地和草地等不同绿色植被碳汇的潜在冲突；基于区域差异，制定具有区域针对性的粮食安全与碳中和协同行动方案。

STUDY ON THE IMPACT OF GRAIN PRODUCTION ON ECOLOGICAL CARBON SEQUESTRATION

Synergy promotion between food security and carbon neutrality is currently a core issue in China, but the impact of grain production on ecological carbon sequestration remains unclear. This paper attempts to clarify the mechanism of grain production''s impact on ecological carbon sequestration, and empirically study the net effect of grain production on ecological carbon sequestration. This paper firstly constructed an analytical framework for the impact of grain production on carbon sequestration. On this basis, the county panel data in China from 2000 to 2017 and the two-way fixed effects model were used to conduct empirically analysis. The baseline analysis showed that grain production had a significant positive effect on carbon sequestration. Heterogeneity analysis showed that a moderate increase of multiple cropping index was helpful to strengthen the carbon sequestration. The impact of grain production on carbon sequestration was greater in eastern and central regions compared with western and northeastern regions. Therefore, we should pay attention to the carbon sequestration attributes of grain production, strengthen soil protection by means of cropping system adjustment, etc., and explore the carbon sequestration potential of grain production; optimize the spatial layout of terrestrial green vegetation and reduce the potential conflict of carbon sequestration of different green vegetation such as farmland, forest and grassland and develop regionally targeted synergistic action plans for food security and carbon neutrality based on regional differences.