Abstract: Improving the carbon efficiency of crop production is one of the important ways to realize the low-carbon agriculture. In order to get a clear understanding of carbon efficiency in agricultural production, this paper, based on the investigation data of the farmer’s production, applying input and output calculation method, evaluated the carbon input, carbon output and carbon efficiency in production of the three major crops, winter wheat, summer maize and cotton, in Wuqiao County of Hebei Province in North China Plain. The results were as follows:the carbon input of winter wheat, summer maize and cotton was 943.47±225.14, 525.74±134.73, and 513.60±138.94 kg CE ha^-1, of which fertilizers and electricity accounted for a majority, about 60% and 25% respectively. The carbon output of the three major crops was 8 430.70±774.45, 7 194.50±754.58, and 5 486.00±547.69 kg CE ha^-1 respectively, of which straw accounted for 50%, economic yield accounted for 34%, and root accounted for 17%. The carbon production efficiency of winter wheat, summer maize and cotton was 7.95±2.55, 15.90±4.34, and 7.60±2.92 kg kg^-1 CE, respectively. The carbon economic efficiency of the three crops was 13.28±4.56, 21.47±5.86, and 76.70±29.45 CHY kg^-1 CE, respectively.The carbon ecological efficiency of the three crops was 9.59±3.07, 14.57±3.98, and 11.69±4.49 kg C kg^-1 CE, respectively. There were significant differences in the carbon efficiency of the three major crops. Preliminary results showed that the carbon integrated efficiency of summer maize was the highest, followed by cotton, which in turn had higher the efficiency than winter wheat in North China Plain.

Key words: North China Plain, Winter wheat, Summer maize, Cotton, Carbon efficiency, Low-carbon agriculture