Enhancing water–energy–food–carbon synergies through crop production optimization: a nexus-based assessment in the Huang–Huai–Hai Plain

This study explores the water–energy–food–carbon (WEFC) nexus in the Huang-Huai-Hai (HHH) Plain, China, focusing on the trade-offs and synergies between food production (FO) and environmental sustainability. From 2000 to 2020, crop production in the region saw increases in water footprint (WF), energy consumption (EC), food output (FO), and carbon footprint (CF), with spatial variations—lower values in the north and higher values in the south. Direct energy and fertilizers were the primary contributors to CF and EC. Most regions showed synergies between FO and resource/environmental indicators, though trade-offs were observed, especially in the north and southeast. Decomposition analysis indicated that WF was primarily driven by the scale effect, while EC, FO, and CF changes were dominated by intensity effects. Scenario analysis demonstrated that combining yield gap closure and planting structure adjustment (Y2-1+P) is the most effective strategy, reducing WF, EC, and CF by 10.5%, 9.2%, and 13%, respectively, while increasing FO by 10.1%. Reducing wheat, maize, and rice cultivation while expanding soybean, peanut, and potato areas presents a viable strategy for decoupling agricultural production from resource and climate pressures. This study provides a nexus-based framework for aligning food security with resource conservation and carbon reduction in intensive agricultural systems, offering insights for policy and planning in global grain-producing regions facing similar water-energy-climate challenges.