Analysis of footprint fluxes and network characteristics in the agricultural water-land-energy-carbon nexus system of the North China Plain

The North China Plain (NCP), as China's second-largest plain and a critical grain-producing region, plays a pivotal role in ensuring national food security. However, the rapid agricultural development has intensified resource-environment conflicts, making the region characterized by significant contradictions within its water-land-energy-carbon (WLEC) nexus system. Understanding the linkages among these four elements is critical for optimizing resource allocation and achieving carbon neutrality goals. This study employed an environmentally extended multi-regional input-output (EE-MRIO) model to quantify direct consumption and embodied flows of agricultural water, land, energy, and carbon in the NCP. Ecological network analysis (ENA) and a coupling coordination degree model were applied to examine network characteristics and interrelationships within WLEC system. The results revealed that: 1) From 2012 to 2017, the direct resource consumption and the embodied flows exhibited upward trends with significant spatial heterogeneity, and the trade-embodied agricultural water use, cropland utilization, energy consumption, and carbon emissions between the NCP and other provinces of China increased by 5.295×10⁹m³(16.5%),1.918×10⁸hm²(3.1%), 1.186×10⁶t(17.2%), and 3.942×10⁷t (20.9%) respectively, thus consolidating the NCP's position as China's primary grain-producing region. 2) In general, virtual agricultural resources flowed predominantly from underdeveloped to developed regions, gradually concentrating in areas with high population density, large economic scale, and active markets. 3) The WLEC network exhibited low cycling ratios with substantial inter-regional disparities, constraining resource mobility. Inter-provincial ecological relationships were dominated by competition and predation, with limited mutualism. The network demonstrated low efficiency, high redundancy, and loose structure. Although the coupling coordination degree of the NCP's WLEC system exceeded the national average, its sustainability capacity requires enhancement. To advance high-quality agricultural development, alleviate resource scarcity, and achieve dual-carbon goals in the NCP, this study proposes three strategic recommendations. First, optimize resource linkages by establishing integrated management mechanisms that consider synergistic effects among water, land, energy, and carbon. Second, improve resource flow pathways through infrastructure development and market-based instruments to enhance system efficiency and reduce redundancy. Third, promote modern, green agricultural practices to simultaneously address resource constraints and emission reduction objectives.