Spatial-temporal characteristics and driving factors of the chemical fertilizer supply/demand correlation network in China

The rational allocation of chemical fertilizer resources is of strategic importance in mitigating agricultural source pollution and achieving agricultural green development. The spatiotemporal correlation of chemical fertilizer supply/demand and its determinants remains unclear. In this study, based on the inter-provincial chemical fertilizer supply/demand panel data of China from 1994 to 2018, an improved gravity model was employed to determine provincial chemical fertilizer supply/demand correlations. Finally, the chemical fertilizer supply/demand evolution and its driving factors were analyzed using social network analysis and a quadratic assignment procedure. The results indicated that (1) the intensity of the spatial relationship of inter-provincial chemical fertilizer supply/demand increased in a fluctuating fashion, but there was still room for improvement. The network structure presented good stability, and the spillover effect exhibited multiple superposition characteristics; (2) the spatial correlation network of inter-provincial chemical fertilizer supply/demand presented a “core-periphery” distribution pattern of the supply, demand, and balance areas. The division of blocks in the network changed in time and space, and some provinces changed their roles and positions in the network during development; (3) chemical fertilizer-related policies (e.g., Exemption Agricultural Tax, Notice on the resumption of value added tax policy on fertilizers, and Rural Revitalization Strategy) have played a positive role in the formation and development of the interprovincial spatial correlation network of chemical fertilizer supply/demand in China; (4) natural conditions and socioeconomic factors interact to promote the formation of the spatial correlation network of chemical fertilizer supply/demand. The differences in the scale of the rural labor force, the scale of agricultural mechanization, the agricultural planting structure, the populations, and urbanization levels all had a significant impact on it. The identification of the spatial characteristics of chemical fertilizer supply/demand correlation networks offers a new perspective on taking various measures to realize the cross-regional coordination of chemical fertilizer resources, strengthen the protection and utilization of agricultural resources, and promote green agricultural development.