Carbon and nitrogen footprints accounting of peanut and peanut oil production in China

The peanut sector has significant potential for decreasing greenhouse gas (GHG) emissions and reactive nitrogen (Nr) loss from agricultural production activity in China. This study calculated the carbon (C) and nitrgen (N) emissions of the peanut sector in China by jointly using the carbon footprint (CF) and nitrogen footprint (NF) methods based on the national statistical data from 2008 to 2017. The results showed that the average area-based CF (CFa) and NF (NFa) of peanut cropping in China were 1912.58 kg CO2-eq ha(-1) and 41.19 kg N-eq ha(-1), respectively. The average yield-based CF (CFy) and NF (NFy) of peanut oil reached 1.38 kg CO2-eq kg(-1) and 28.23 g N-eq kg(-1), respectively. The CFa of the peanut cropping subsystem in China increased from 2008 to 2017, while the NFa presented a reduction feature during 2009-2011 and during 2015-2017. Based on the results above, the total GHG emissions and Nr losses caused by the peanut sector in China were estimated to reach average values of 8.33 million tons (Mt) CO2-eq year(-1) and 0.15 Mt N-eq year(-1), respectively, during 2009-2017. Moreover, peanut cropping in Fujian showed the highest CF and NF, while that in Anhui and Chongqing presented the lowest CF and NF, implying that optimizing peanut layout in China would be of significant importance to developing the peanut sector with fewer environmental consequences. Fertilizer production and application were continuously the largest sources of CF and NF in the peanut sector in China, which should be given more attention for reducing the environmental consequences in the future. This study provides policy guidance for clean production in peanut industrial chain in the China.