Coupling Coordinated Development of Urbanization and Soil Conservation Ratio in the Loess Plateau Region of China

With the implementation of various ecological restoration and regional development policies, both urbanization and soil conservation in the Loess Plateau (LP) have advanced substantially, but conflicts between development and the ecological environment are becoming increasingly prominent. Soil conservation is a key regulating ecosystem service, and understanding its interaction and coupling mechanism with urbanization is crucial for achieving sustainable urban development. This study used multi-source remote sensing data and evaluated soil erosion and conservation status over the past 30 years based on the revised universal soil loss equation (RUSLE) model. In addition, the coupling coordination degree model (CCDM) was employed to investigate the spatiotemporal characteristics and reveal the mechanism of the coupling coordinate degree (CCD) between soil conservation rate (SCR) and urbanization index (UBZ). Results indicate that: (1) soil erosion intensity (SE) has been well controlled in the Loess Plateau in recent decades, and the SCR has an obvious upward trend, but there is a risk of soil erosion worsening in the urban agglomeration area; (2) the coupling coordination degree between UBZ and SCR has improved significantly in the research period, but it is still concentrated in the southeast of the Loess Plateau and around the provincial capital cities; (3) there is a very significant logarithmic function fitting relationship between UBZ and CCD. At present, UBZ is the main factor leading CCD, and cities need to pay attention to controlling SE to maintain the stable growth rate of CCD when they develop to a certain period. This study pioneers the integration of multi-source remote sensing data with the RUSLE-CCDM framework to quantify a logarithmic relationship between urbanization and soil conservation coupling in the LP, proposing a phased constraint-incentive-restoration governance strategy aligned with environmental thresholds.