Based on the China net primary productivity data of vegetation from 2006 to 2019, the distribution data of three staple crops, and agricultural production inputs, this article estimates the carbon sink, agricultural carbon emissions, and carbon footprint of China’s three staple crops, and analyze the spatial and temporal patterns of carbon sinks in the three staple crops. The results show that 1) from 2006 to 2019, the total carbon sequestration of the three staple crops in China continues to increase, with rice, maize, and wheat accounting for 41.92%, 38.62%, and 19.46%, respectively. The carbon sequestration capacity of three staple crops far exceeds the carbon emissions caused by agricultural production factors, with a ratio of 5.37:1, indicating that the China agricultural ecosystem has a strong carbon sequestration capacity. 2) The total agricultural carbon emissions in China have continued to increase, but the growth rate has decreased. Fertilizer and diesel are the main carbon sources. 3) The ecosystem of three staple crop farmlands shows a significant carbon ecological surplus. The carbon footprint in 2019 is 17.55×10⁶ hm², accounting for 18.62%, which means that the CO₂ emissions from the production of the three staple crops farmland system are reduced to less than 1/5 of the China three staple farmland to absorb. The results can help clarify their position in the carbon cycle and provide important scientific basis for promoting agricultural carbon emission reduction, achieving “carbon peak” in 2030 and “carbon neutral” in 2060.

基于2006—2019年全国NPP、三大粮食作物分布和农业生产投入等统计数据, 对中国三大粮食作物的碳汇量、农业碳排放量和碳足迹进行估算, 并分析三大粮食作物碳汇量的时空格局。结果表明, 1) 2006—2019年全国三大粮食作物总固碳量持续增加, 其中水稻、玉米和小麦的固碳量分别占41.92%, 38.62%和19.46%; 三大粮食作物的固碳量远超出农田生产要素引起的碳排放量, 两者之比为5.37:1, 表明全国农田生态系统具有较强的固碳能力; 2) 全国农业碳排放总量持续增加但增速下降, 化肥和柴油是主要碳源; 3) 三大粮食作物耕地生态系统表现出较大的碳生态盈余, 2019年碳足迹为17.55×10⁶ hm², 占耕地比例为18.62%, 即三大粮食作物耕地系统生产排放的CO₂降低至需要全国不到1/5的三大粮食作物耕地来消纳。研究结果有助于明晰耕地生态系统在碳循环中的地位, 对促进农业碳减排, 全国2030年实现“碳达峰”, 2060年实现“碳中和”的战略提供科学依据。