Trends, distribution, and impact factors of carbon footprints of main grains production in China

China is the largest emitter of greenhouse gas (GHG) and has the largest agriculture production in the world, and thus, fully understanding the country's agricultural GHG emissions is of considerable importance. This study evaluates the critical processes, patterns, and impact factors of the carbon footprint of grain production in China based on a new scale data set: agricultural statistics data of over 300 prefecture-level regions. Results show that fertilizer application, straw burning, and methane emissions in rice paddy are the main causes of GHG emissions. High production carbon footprint (PCF) typically appears in areas with low crop yield, whereas low PCF appears in areas with intensive pro-duction. Longitude, altitude, and per unit yield are significant correlated with the methane emissions in rice paddy. The increase in GHG emissions from fertilizer application on per unit crop yield highly contributes to the increase in PCF. Moreover, longitude, latitude, and soil properties are the most important factors in PCF variation. Promoting large-scale and intensive modern agriculture production remains a key measure to mitigate GHG emission. Findings can improve the understanding of China's agricultural GHG emissions and subsequently be translated into management suggestions for GHG mitigation. (C) 2020 Published by Elsevier Ltd.

Automated summary

This study evaluates the carbon footprint of grain production in China and identifies fertilizer application, straw burning, and methane emissions in rice paddy as the main causes of GHG emissions. Results show differences in PCF between high production and low production areas, emphasizing the importance of fertilizer application in PCF increase. The study suggests promoting modern agriculture production as a key measure to reduce GHG emissions.