Exploiting the potential of carbon emission reduction in cropping-livestock systems: Managing water-energy-food nexus for sustainable development

Water, land, energy, and agricultural waste are essential resources for agriculture that require systematic allocation to achieve efficient utilization and support the objectives of “carbon peak and neutrality”. In this study, a novel optimization model framework was proposed to manage the water-energy-food nexus (WEFN). In this framework, the system scope is determined and the mass and energy flows within the system are analyzed. Based on bi-level multi-objective programming (BMP), the optimization model aims to reduce risk and greenhouse gas (GHG) emission, ensure food security, and promote economic growth, coupled with the uncertainty method including, fuzzy numbers and stochastic numbers, as well as fuzzy possibility entropy. Therefore, the framework is capable of: (1) generating sustainable cross-sectoral WEFN management strategies and proper agricultural waste disposal modes; (2) measuring the optimization-based agricultural GHG emission reduction potential in agricultural cropping-livestock system; (3) dealing with the leader-follower relationships, varying decision-making preferences, and multiple uncertainties in agricultural system. The proposed framework was applied to Wuwei, Northwest China, generating agricultural scale adjustments, water allocation, and agricultural waste disposal schemes in different hydrological years. The results showed that agriculture in Wuwei remains a carbon source after optimization: plant sequestration is the only carbon sink of 82.3–107.4 × 108 kg CO2-eq, and the total carbon emissions are 155.4–165.3 × 108 kg CO2-eq, of which animal husbandry accounts for 54.8 %. All crop straw and 91.6 % of livestock manure are recycled into feed and organic fertilizer, respectively, leading to a total carbon emission reduction of 96.3 × 108 kg CO2-eq. The system performances have been improved in all aspects compared to the status quo, confirming the effectiveness and superiority of the framework. The proposed framework can coordinate agricultural resources from a more holistic perspective, provides a practical basis for sustainable agricultural development, and can be applied to other regions for sustainable agricultural management.