Spatiotemporal changes and drivers of net greenhouse gas emissions from major cropping systems in China during 1984–2018

Abstract

China is one of the largest emitters of greenhouse gas emissions from croplands. However, the spatiotemporal patterns and drivers of net greenhouse gas emissions (NGEs) in Chinese major cropping systems have not been well identified. Here, we conduct a comprehensive investigation of NGEs from 21 cropping systems at the province level over 1984–2018 and their 13 major drivers using process-based and statistical models with updated datasets. The total NGEs increased by 36.7 % (30.1 %∼41.7 %) during this period, reaching 821.4 (682.1∼952.4) Tg CO₂-eq yr^-1 in 2018, due to the significantly increased harvest area and per unit area NGEs. Among the four components of NGEs, the CO₂-eq emissions associated with agricultural management contributed most. Single rice, vegetables, early-late rice, winter wheat-single rice, spring maize, and winter wheat-summer maize rotation systems were the top six emitters. Synthetic nitrogen fertilizer application, rice cultivation and initial soil organic carbon change were the primary drivers. Our findings identify the priority areas, cropping systems and drivers to mitigate NGEs, facilitating the realization of low-carbon and green agriculture in China.