Towards sustainable circular agriculture: An integrated optimization framework for crop-livestock-biogas-crop recycling system management under uncertainty

Abstract

ContextGrowing socio-economic development and population poses unprecedented challenges for agriculture in meeting increasing demand of food, water, and energy. Rethinking the future agricultural production to simultaneously safeguard resources security and regulate environmental pollution is essential. Circular agriculture opens up a new path for the high-efficiency and environmental-friendly production. An integrated energy-water-food nexus optimization approach for managing agricultural resources and wastes in line with the principles of sustainable circular agriculture management is lacking. ObjectiveThis study therefore proposes an integrated uncertain optimization model to manage agricultural crop-livestock-biogas-crop recycling systems from a cross-sectoral energy-water-food nexus perspective in the changing environment. The aims are to: (1) balance objectives of input reduction, output promotion, ensuring equity, and global warming mitigation; (2) generate sustainable resources allocation strategies based on efficiency and recycling; (3) assess the global warming mitigation potential of the recycling systems from a life cycle perspective; and (4) deal with interactions, complexities, uncertainties, and risks existed in the recycling systems. MethodsThe proposed model framework is based on a stochastic multi-objective programming, while triangular fuzzy numbers, fuzzy credibility constrained programming, Stewart model, analytic hierarchy process, and opportunity carbon footprint are integrated to enhance its practicability and feasibility. The model is verified through a real-world case study in the Zhanghe Irrigation District, Hubei province, China. Results and conclusionsResults show that optimal water and land resources allocation solutions are more efficient than current strategies, with water consumption per unit area decreasing by 13.63% and rice production per unit area improving by 22.06%. Paddy field and biogas leakage are two of the largest sources of GHG emission, calling for agronomic and engineering measures to improve farmland management and biogas generation technology. Livestock breeding contributes 10% of the total GHG emission, along with generating 76% of the total biogas, indicating the great significance of manure recycle. Overall, 4.26 × 108 kg CO2 is reduced in the recycling system, contributed by chemical fertilizer reduction, agricultural wastes recycle, and non-renewable energy replacement. SignificanceThe study offers a potential nexus optimization approach for sustainable management of agricultural recycling systems from a holistic perspective. It can be used as a general model to extend to other agricultural systems suffering from similar resources and environmental crisis.