Assessing the carbon emissions from fertilizer use reduction in China

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 7185.11×104t in 2008 to 8462.78×104t in 2014, and then decreased to 7004.40×104t 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. © 2024 Chinese Society for Environmental Sciences. All rights reserved.