Dynamics of Vegetation and Soil in Long-Term Artificial Sand Control Projects in the Ulan Buh Desert

Desertification is a severe ecological problem worldwide under global change. China has devoted extensive and effective efforts to desertification prevention and sand control. However, the long-term effectiveness of artificial sand control, particularly its impact on vegetation and soil evolution, remains understudied. To clarify the effect of different years of restoration on plant community characteristics and soil properties, and the overall succession trend of vegetation and soil during long-term restoration, this study carried out a field investigation in the straw checkerboard barriers under different years of restoration (0 year: unrestored stage; 1, 5 years: initial stage; 10, 15 years: late stage) in the Ulan Buh Desert. Comprehensive evaluation models were used to quantify vegetation and soil improvement under restoration efforts, and a vegetation-soil coupling coordination degree model was employed to explore their coordination level over different restoration periods. Results showed significant differences in plant species diversity among restoration years (p < 0.05). Plant diversity indices and coverage in the late stage of restoration were significantly higher than those in the unrestored and initial stages. After 10 years of restoration, the indicator species of sand fixation Artemisia desertorum reached maturity, relatively stable near-natural communities. Meanwhile, leaf and root nutrient contents had inflection points in this stage. Soil properties varied significantly across restoration years (p < 0.05). The comprehensive evaluation indices of vegetation growth and soil quality peaked around the 10th year of restoration and then tended to stabilize. The coupling coordination degree between vegetation and soil was 0.63 in the 10th year of restoration, suggesting that the vegetation-soil system was in a state of well-coordinated development. Taken together, vegetation and soil succession tended to stabilize after 10 years of artificial sand control. These results will provide a theoretical basis for sand control projects, especially for the late-stage management of the projects.