Carbon Footprint of Mechanized Farming Practices in Cereal Production on the North and Northeast China Plains

Mechanization is expanding rapidly in developing countries. However, long-term use of agricultural machinery is projected to result in additional carbon emissions. Actually, major changes in mechanized production have already occurred, affecting agricultural systems' environmental performance. This study aims to assess the effects of mechanical operations (including tillage, seeding, irrigation, harvesting, etc.) on carbon emissions throughout the crop growing season and to explore ways to reduce emissions. Irrigated winter wheat-summer maize on the North China Plain and rainfed spring maize on the Northeast China Plain represent interesting examples as this region is the major cereal cropping system, including area, mechanization level, and socio-economic features. The methodology considers the effects of a single and/or a series of agricultural machinery operations and different variants of the machinery operation chain or different technologies on carbon emissions. A mechanical operational carbon footprint was estimated through an agricultural footprint model using mechanical energy consumption of 454 farms observed. Data were obtained from a face-to-face questionnaire. Results suggest that approximately 50.6% and 39.2% of the carbon footprint of wheat and maize, respectively, were caused by irrigation practices on the North China Plain. Carbon emissions were significantly lower with water-saving irrigation technologies because of higher efficiency of mechanical operations. Regarding the Northeast China Plain, where 46.6% of carbon emissions were generated by maize tillage operations. Conservation tillage could reduce carbon emissions by reducing mechanical power consumption. Therefore, adoption of water-saving irrigation technology is recommended in irrigated areas and conservation tillage practices are recommended in rainfed agricultural areas to reduce the carbon footprint on the North and Northeast China plains