China is a major producer of wheat, maize and rice, which generates massive greenhouse gas emissions due to the consumption of elevated amounts of energy, land, and water, yet there is actually few knowledge on the spatial heterogeneity of greenhouse gas emissions. Here, we introduce a polyphasic approach to quantify the emissions from the land, energy, and water in Chinese cereal production. Results show that total greenhouse gas emissions from wheat, maize and rice crops reached 505.5 Tg CO2eq, including 247.5 Tg CO2eq for the land, 222.1 Tg CO2eq for energy, and 35.9 Tg CO2eq for water. The major greenhouse gas contributors are the land, of 55.8%, and energy to produce nitrogen fertilizers, of 30.5%. Moreover, greenhouse gas emissions from cereal production show large-scale spatial heterogeneity at the provincial scale due to differences in crop type, natural resources, and managerial practices. The collective adoption of green technologies and reasonable food trading practices could reduce greenhouse gas emissions from the cereal production supply chain, further promoting the carbon neutrality of agriculture.
