A resource bi-level optimization model of water-energy-food-carbon nexus in a regional agricultural system under multi-stakeholder conditions

The conflict between low-carbon development, energy security, and resource shortages presents significant challenges to agricultural advancement. Thus, the aim of this study is to achieve the sustainable management of agricultural resources. To this end, a bi-level optimization model for agricultural resources is developed. This model examines the interrelation among water-energy-food-carbon, assesses the efficiency of bioenergy production within regional agricultural systems, and facilitates the balancing of objectives among different stakeholders. Key decision variables include water resource allocation, crop planting areas, and livestock populations. At the upper decision-making level, the model seeks to maximize agriculture economic benefits, reduce carbon emissions, improve bioenergy production efficiency, and minimize land resource inequality. At the lower decision-making level, it prioritizes economic benefits and yield of agricultural products. To solve the model, an integrated approach combining weighted bias and fuzzy methods was utilized. To validate the model's applicability, a case study was conducted in Sichuan Province. The results demonstrated that, after optimization, agricultural water resource allocation reached 168.56 × 108 m3. Planting areas for vegetables, rice, and tubers decreased by 0.78 %, 5.46 %, and 1.54 %, respectively, while livestock populations for pigs, cattle, and sheep declined by 29.91 %, 11.75 %, and 7.46 %. The regional average bioenergy production efficiency was 12218.08 KJ/MJ. Notably, the indirect carbon emissions caused by CH4 emissions accounted for 50.51 % of total emissions. The proposed model outperformed alternative approaches, effectively balancing multi-level objectives and providing a robust framework for optimizing agricultural resource management while addressing stakeholder conflicts.