大气中温室气体浓度的增加引起的全球气候变化成为威胁人类生存和发展的一大难题。农作物的碳汇功能对气候变化也起着重要的调节作用。农作物的生产过程既是碳源也是碳汇。本文收集整理分析了我国主要农作物农作系统的相关碳排放参数，估算了农田碳汇碳源效应及其动态变化特征，对作物生产系统的碳投入产出进行定量评价。为我国发展低碳农业规划、政策制定提供了依据，并提出了我国农田碳汇结构的优化途径。

The global warming caused by heavy emissions of greenhouse gases has posed a great threat to the existence and development of mankind. The carbon sink function of crops has an important regulating effect on climate changes. Actually the production of crops can be seen as the carbon source as well as the carbon sink. In this article, the authors gather and analyze the relevant carbon emission parameters of the staple crop production system in China, estimate the carbon sink effect of farmland and its dynamic change feature and quantitatively evaluate the carbon input and output of these crop production systems. In this way, the paper provides a basis for making the low-carbon agriculture planning and policies and proposes the approach to optimizing the carbon sink structure of the farmland in China.