Research on the Coupling Coordination Degree andInfluencing Mechanisms of the Water and Soil ResourcesSystem in the Northern Sandy Belt

The Northern Sandy Belt, a key ecological barrier and fragile zone in China, has its regional sustainable development determined by the coordination status of its water and soil resources system. This study takes the Horqin-Hunshandake Sandy Area as the research object. Based on data from 2006 to 2022, we established an adaptive evaluation system consisting of 18 indicators, and combined the coupling coordination degree model with Tobit regression to reveal the evolutionary characteristics and influencing mechanisms of the system’s coupling coordination. The results show that:(1) During the study period, the coupling coordination degree showed a fluctuating upward trend, rising from 0.367 in 2009 to 0.602 in 2021. The coordination status shifted from mild imbalance to basic coordination, but its stability was insufficient, with significant declines in 2017, 2019, and 2022;(2) There was significant spatial differentiation: Tongliao City had the highest and most stable coordination level, while Hinggan League had the lowest, and Xilingol League experienced the most drastic fluctuations. Regional differences are closely linked to the natural background and socio-economic patterns;(3) The system development exhibited phased transitions: the water resources system dominated from 2006 to 2014, while the contribution of the land resources system increased from 2015 to 2022;(4) Annual precipitation had a significant positive promoting effect on the coupling coordination degree, while annual water consumption had a significant negative inhibiting effect; population pressure indirectly affected the system balance through resource demand.

This study indicates that water resources are the core constraint for the development of the Northern Sandy Belt, and exceeding the carrying capacity will lead to system imbalance. For future development, it is necessary to adhere to the principle of "determining land use and production based on water availability", strengthen rigid constraints on water resources, implement differentiated management, and build a monitoring and early warning system to achieve sustainable development. This study provides a scientific basis for the optimal allocation of regional water and soil resources and ecological management.