Structural characteristics and evolutionary mechanisms of the global potash resource trade network: a TERGM-based empirical analysis

With rising agricultural demand, persistent spatial mismatch between potash supply and demand, and increasing uncertainty in global resource supply chains, the structural stability and evolutionary adjustment of the global potash resource trade network (GPRTN) have become increasingly important for resource security and food-system stability. Based on bilateral potash trade data from 2000 to 2023, this study employs complex network analysis and a Temporal Exponential Random Graph Model (TERGM) to examine the structural characteristics, evolutionary patterns, and dynamic driving mechanisms of the GPRTN. The results show that the GPRTN has experienced enhanced connectivity, improved resource-flow efficiency, and increasing structural differentiation. Although trade flows have become more diversified, the network remains dominated by a small number of hub economies, and its community structure has gradually shifted towards a multipolar regional configuration. The TERGM results show that geographical proximity has the strongest positive effect, with a coefficient of 2.4087, followed by organisational proximity, indicating that transport costs, logistics accessibility, spatial proximity, and historical organisational linkages are key conditions shaping potash trade ties. The significantly positive mutual effect, with a coefficient of 0.8779, together with temporal dependence terms, indicates strong reciprocity, relationship persistence, delayed reciprocal adjustment, and path dependence in the GPRTN. Node attribute results show that countries with stronger economic capacity, higher agricultural production intensity, greater agricultural input demand, and higher market openness are more likely to participate in potash trade. Negative nodematch effects, represented by node-match.GDP (−0.5356), indicate that trade ties are more likely to form between countries with larger attribute differences, reflecting functional complementarity and import dependence between major demand-side economies and resource-endowed suppliers. This study provides empirical evidence for understanding the systematic evolution of the GPRTN and improving global potash resource allocation security and supply-chain resilience.