Optimized model for coordinated development of regional sustainable agriculture based on water–energy–land–carbon nexus system: A case study of Sichuan Province

In the context of global warming and resource scarcity, economic development and population growth are challenging the demand for water and land resources, and the complex relationship among water, land, energy and carbon dioxide makes it important that a process for efficiently managing water, energy, land and carbon dioxide in sustainable agricultural systems is developed. Therefore, considering the uncertainty of agricultural systems, this paper proposes a multiobjective optimization model for the sustainable management of water–energy–land–carbon dioxide systems that optimizes the allocation of water resources and land resources under the condition of minimizing agricultural carbon emissions and maximizing irrigation water productivity and energy economic productivity. The model uses the improved nondominated sorting genetic algorithm to address this issue, and the optimal resource allocation strategy is further obtained through the multiobjective decision model. This paper uses Sichuan Province, the main grain-producing region in Southwest China, as a case study to verify the effectiveness of the model and then provide a decision-making process for improving the utilization rate of agricultural resources and developing low-carbon agriculture. The results show that under the coordination of resource consumption, economic benefits and carbon emissions, the total allocation of water resources and the total allocated area of crop planting after optimization were 118.678 × 108m3 and 4598.796 × 103ha, respectively, decreases of 22.87% and 7.9%. The planting structure changed. The area planted with rice increased by 4.25%, the area planted with corn decreased by 15.5%, and the area planted with rapeseed decreased by 14.96%. Electricity, fertilizer and straw burning contributed significantly to agricultural carbon emissions, with average contributions of 68.0%, 15.9% and 6.6%, respectively. The multiobjective optimization model established in this paper can improve resource utilization and reduce the environmental impact of agriculture, which are of great significance in terms of achieving the goal of "carbon neutrality" and promoting the sustainable development of regional agriculture. The established model framework can be applied to regions with limited resources around the world.