Research on the Coupling Coordination Relationship and Spatial Equilibrium Measurement of the Water–Energy–Food Nexus System in China

In the context of continued global population growth and various environmental challenges, the coordinated protection of water resources, energy, and food security has become increasingly important. This study focuses on the uneven distribution of water resources, food, and energy in China, examining the coupling coordination relationship within the Water–Energy–Food nexus (WEF) system from 2006 to 2020 and conducting a quantitative assessment of its spatial equilibrium state. The results indicate the following: (1) The WEF system coupling degree across China’s provinces (municipalities and autonomous regions) is above 0.75, suggesting a close interdependence and synergy between water resources, energy, and the food system. Most regions maintain a dynamically balanced coupling coordination state over time, providing theoretical feasibility for optimizing the allocation of cross-regional and cross-system resources. (2) Natural endowments and human activities have a decisive impact on spatial equilibrium differences in the water resources system. The layout of energy production is closely related to equilibrium, and overly concentrated production areas can disrupt spatial equilibrium. Future energy planning must consider the synergistic relationship between production and consumption areas. The proportion of grain output is not positively or negatively correlated with the spatial equilibrium coefficient; if regions with concentrated or sparse grain production cannot coordinate their development, the overall spatial equilibrium level will decline. (3) The spatial equilibrium of the WEF system is superior to that of any single subsystem. Inherent deficiencies in natural endowments can be gradually adapted and maintained through policy adjustments, resource coordination, and regional collaboration, allowing the system to maintain a dynamic balance.