Assessing the impacts of farmland use transition on the food–water–energy–pollution nexus in grain production: An integrated simulation framework

Farmland use transition in developing countries, characterized by concurrent shifts in dominant and recessive morphologies, profoundly reshapes the food-water-energy-pollution (FWEP) nexus in grain production. Yet, integrated assessment remains limited by methodological gaps between spatial and behavioral simulations. This study bridges this divide by developing a PLUS-ABM framework that couples high-resolution land-use change modeling (PLUS) with agent-based decision simulation (ABM). We apply the framework to Taojiang County, China—a representative grain-producing region undergoing rapid farmland use transition. The results reveal significant farmland contraction and eastward spatial shifts driven by urbanization. Agent-based simulations indicate accelerating land concentration, with large-scale operators controlling 58% of farmland by 2023 and expected to expand further. FWEP assessments reveal scale-dependent trade-offs: medium-scale farms achieve the optimal FWEP balance (high yield, moderate energy and water use, low pollution), whereas large-scale operations experience 3.2–6.8% yield penalties, 9.4–11.3% higher energy costs, and significantly elevated pollution despite gains in water efficiency. Projections indicate a worsening of the FWEP paradox (declining yields and elevated environmental burdens) under current transition pathways, primarily due to the expansion of large-scale farming. We argue that current misaligned, area-based subsidies exacerbate these trade-offs by incentivizing suboptimal farm scales. Policy reforms should shift toward performance-based compensation, prioritizing FWEP-optimized medium-scale operations and eco-oriented interest-based farmers, while establishing strict ecological constraints for large holdings. This integrated approach offers actionable pathways for aligning farmland transitions with sustainable resource governance.