Spatial-Temporal Evolution Characteristics of Agricultural Intensive Management and Its Influence on Agricultural Non-Point Source Pollution in China

The influencing mechanism of agricultural non-point source pollution under intensive agricultural management is complicated. This paper adopted provincial panel data from 2008 to 2020 to estimate the level of agricultural intensive management, the agricultural chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) emissions and emission intensity of agricultural non-point source pollution in different regions of China and analyze the spatial-temporal differentiation characteristics. Moreover, the mediation effect model and spatial spillover effect model were adopted to further explore the influence mechanism of agricultural intensive management on agricultural non-point source pollution. The results show that (1) The total emissions and emission intensity of agricultural non-point source pollution both showed an increasing trend, and these areas with high levels of agricultural non-point source pollution are roughly consistent with those areas with high-level of agricultural intensive management. (2) At the overall level, there were mediating effects of natural ecology, agricultural land management, planting and rearing structure and pollution control investment between the relationship of agricultural intensive management and agricultural non-point source pollution, among which agricultural land management was the largest. Additionally, there was significant spatial heterogeneity in the influencing mechanism of agricultural intensive management on non-point source pollution. (3) There were significant spatial agglomeration characteristics in both agricultural intensive management and agricultural non-point source pollution, which showed a fluctuating trend of “rise-decline-rise-decline”. (4) Agricultural intensive management has a significant positive spatial spillover effect on COD, TN and TP emissions of agricultural non-point source pollution. However, environmental regulation could cause agricultural non-point source pollution to be transferred nearby. Scientific understanding of the spatio-temporal differentiation characteristics and influencing mechanism of agricultural non-point source pollution under the agricultural intensive management model is conducive to providing reference for policy regulation.