中国化肥减量降碳效应评估

Assessing the carbon emissions from fertilizer use reduction in China

从2008~2014年、2014~2020年和2020~2025年3个时段,基于总量变化和强度贡献两个维度,对中国化肥使用减量降碳效应进行评估.结果表明:(1)中国化肥使用碳排放总量由2008年的7185.11万t波动增加到2014年的8462.78万t,然后持续减少到2020年的7004.40万t.前者增幅17.78%,后者减幅17.23%.玉米和棉花化肥使用碳排放总量峰值出现在2014年,其余农作物则在2014年之前.(2)2014~2020年,化肥使用强度减少的降碳贡献程度为81.08%,其中,大豆和烤烟的贡献程度低于50%,棉花化肥使用强度增加.不同省份化肥减量降碳效应差异明显,其中,河北、黑龙江、海南和甘肃化肥使用强度减少的贡献程度低于50%.江苏、广东和新疆化肥使用强度增加.(3)相较2020年,在保障种植规模和优化种植结构的前提下,2025年化肥使用碳排放总量将下降.化肥使用强度减少1%情景下,稻谷、小麦、棉花、糖料和蔬菜在2025年的碳排放总量低于2020年,玉米、烤烟和大豆则分别需减少3%、5%和10%.稻谷、小麦和棉花化肥使用强度减少1%的降碳贡献程度超过50%,而玉米和糖料需减少3%,烤烟、蔬菜和大豆分别需减少5%、7%和10%.在所设情景下,2025年油料化肥减量降碳效应不明显.中国化肥使用碳排放已达峰,应该进一步提高化肥后“碳达峰”时期减量与降碳的协同性.当前需重点关注化肥使用强度增加和化肥使用强度减少降碳贡献程度不高的地区,区分农作物类型开展化肥减量降碳的总量和强度调控.

The carbon emissions from fertilizer use reduction in China was assessed from three periods of 2008~2014,2014~2020 and 2020~2025,based on two dimensions of total amount change and intensity contribution..The results showed that:①Total carbon emissions from fertilizer use in China increased from 7185.11×10^(4) t in 2008 to 8462.78×10^(4) t in 2014,and then decreased to 7004.40×10^(4) t in 2020.It increased by 17.78%from 2008 to 2014 and then decreased by 17.23%from 2014 to 2020.The peak of total carbon emissions from fertilizer use of corn and cotton occurred in 2014,and other crops appeared before 2014.②The contribution of fertilizer reduction to carbon reduction was 81.08%from 2014 to 2020.Among them,the contributions of soybean and tobacco were lower than 50%.Meanwhile,the intensity of fertilizer use of cotton increased.The carbon emissions from fertilizer use reduction in different provinces has varied significantly,among which,the contributions of fertilizer reduction to carbon reduction in Hebei,Heilongjiang,Hainan and Gansu wer below 50%,and the intensity of fertilizer use in Jiangsu,Guangdong and Xinjiang increased.③Compared with 2020,the total carbon emission from fertilizer use will decrease in 2025 under the premise of securing the planting scale and optimizing the planting structure.The total carbon emissions from fertilizer use of rice,wheat,cotton,sugar and vegetables in 2025 under the 1%reduction scenario are lower than those in 2020,while the fertilizer use of corn,tobacco and soybean need to be reduced by 3%,5%and 10%,respectively.Fertilizer use reductions of 1%of rice,wheat and cotton contribute more than 50%of the carbon reduction,while the fertilizer use of corn and sugar require 3%reductions,and tobacco,vegetables and soybeans require 5%,7%and 10%reductions,respectively.Under the scenarios,the contribution of fertilizer reduction to carbon reduction of oilseeds is not significant in 2025.China's carbon emissions from fertilizer use have reached their peak.The next step should be focused on improving the synergy between fertilizer reduction and carbon reduction in the post-carbon peak period.At present,the areas where the intensity of fertilizer use increased and the contribution of fertilizer reduction to carbon reduction was not high need to be given more attention.The regulations of the total amount and intensity of fertilizer reduction and carbon reduction by crop types should be implemented.