Understanding the nonpoint source pollution loads' spatiotemporal dynamic response to intensive land use in rural China

Abstract

The extensive use of land resources and environmental pollution in rural areas are two major problems prevalent in China and even the world. It is unknown whether improving the degree of intensive use of rural land can reduce environmental pollution; whether environmental pollution will be promoted or inhibited still lacks in-depth discussion. This paper first provides a theoretical analysis of the generation process of nonpoint source pollution loads (NPSP) in rural land use (RLU) and the mechanism and path of intensive rural land use (IRLU) to reduce agricultural nonpoint source pollution loads (ANPSP). Then, it takes 31 provinces in China from 1978 to 2019 as the research object to examine the temporal and spatial evolution features of IRLU and ANPSP. Furthermore, the paper uses the decoupling model and the Environmental Kuznets curve (EKC) model to test the linear and nonlinear relationship between the two. The research shows that the degree of IRLU in China decreased from 0.54 in 1978 to 0.27 in 2006, and then continuously increased to 0.56 in 2019. Moreover, the ANPSP continued to increase from 1955.14 t in 1978-3622.74 t in 2019. The decoupling relationship between the degree of IRLU and environmental pollution experienced the evolution process of "negative decoupling-decoupling", and the EKC had an "inverted N-shaped" characteristic. Overall, China shows that the IRLU helps to reduce ANPSP. At the same time, it was also found that there is obvious heterogeneity among the 31 provinces used in this research in China. Among them, the degree of intensive land use (ILU) in the principal grain-producing regions tends to be better and stable, while other areas show fluctuating changes. The ANPSP in economically developed areas gradually decreases, while that in underdeveloped areas continues to increase. More than 80% of the provinces in China show a trend of IRLU to advance the reduction of ANPSP, but there has also been an increase in the over-intensification of RLU in some major grain-producing areas. The research concludes that there is an inevitable relationship between RLU and ANPSP. Appropriately increasing ILU has a positive effect on decreasing ANPSP.

Keywords: China; Decoupling theory; EKC hypothesis; Intensive land use; Nonpoint source pollution; Spatiotemporal characteristics.