The effect of optimizing chemical fertilizers consumption structure to promote environmental protection, crop yield and reduce greenhouse gases emission in China

To ensure food security, simultaneously achieving environmental protection and greenhouse gas (GHG) emission reduction has become a significant challenge in the sustainable development of China's chemical fertilizers (CFs) industry. Hence, this work attempt to construct a multi-objective optimization model (MOOM) based on crop yield, environment protection, and GHG emissions to adjust and optimize China's CFs structure (nitrogen, phosphate, potash, and compound fertilizers). The findings revealed that it's impossible to achieve the coordinated development of the three objectives only through the adjustment of CFs structure. Different optimization measures were sequentially integrated with the MOOM to innovatively obtain the most suitable optimization schemes and the quantitative adjustment interval (which was compared with those in 2018) of the CFs structure. The following are the specific conclusions. First, compared with 2018, the appropriate increase interval for the total CFs consumption was 9 %-21 %, in which the proportion intervals of nitrogen, phosphate, potash, and compound fertilizers were 18 %-25 %, 12 %-18 %, 7 %-12 %, 48 %-60 %, respectively. Second, the reduction ranges of environmental impact and GHG emissions were 1.1 %-12 % and 12.2 %-16.4 %, respectively, under the optimal scheme (combination of the synergy of organic fertilizer substitution and technology improvement with the MOOM), and the growing range of crop yield was 0.2 %-52 %. The main contribution of this work is to build a methodology system for the adjustment and optimization of CFs consumption structure. The findings of the study could be used by the government to develop relevant policies and by other sectors to perform multi-objective optimization.