Background Sandy desertification represents one of the most severe environmental challenges in arid and semi-arid regions, particularly threatening agricultural productivity and ecosystem stability. To address this critical issue and evaluate the effectiveness of ecological restoration initiatives, this study investigated the impact of different vegetation restoration modes on soil improvement in sandy areas following the implementation of comprehensive sand control and prevention projects. The research focused on understanding how various plant species contribute to soil rehabilitation processes, providing essential scientific foundation for large-scale ecological restoration programs in similar environmental conditions.

Methods This comprehensive field study was conducted in the Sangye Sand Control Demonstration Area of Shannan, Xizang, located within the ecologically sensitive Yajiang River Valley. Five distinct vegetation restoration patterns were selected as study objects, representing different approaches to sandy land rehabilitation: Caragana korshinskii (a drought-resistant leguminous shrub), Corethrodendron scoparium (a hardy perennial legume), Salix cheilophila (a native willow species), Sophora moorcroftiana (a high-altitude adapted shrub), and Hippophae rhamnoides (sea buckthorn, known for nitrogen fixation capabilities). Systematic soil sampling was conducted across different soil layers from the surface to 100 cm depth, allowing for detailed vertical profile analysis. The physicochemical properties of soils under each vegetation restoration pattern were meticulously analyzed using standardized laboratory procedures, including measurements of soil structure, water-holding capacity, nutrient content, and other key indicators of soil quality improvement. Furthermore, in this study, single-factor analysis of variance, entropy weighting, and comprehensive evaluation index methods were used to analyze and evaluate the physical and chemical properties of soil in different soil layers at depths of 0−100 cm for different vegetation types.

Results The comprehensive analysis revealed significant variations in soil improvement effectiveness among different vegetation restoration methods. S. cheilophila demonstrated superior performance in enhancing soil physical properties, showing marked improvements in reducing soil bulk density, increasing capillary porosity, and enhancing water retention capabilities including capillary water-holding capacity, saturated water content, and field water-holding capacity. H. rhamnoides ranked second in overall soil physical property improvement, indicating its substantial contribution to soil structure enhancement. Statistical analysis confirmed that the effects of different vegetation restoration methods on soil nutrient dynamics were significantly different (P < 0.05), demonstrating the importance of species selection in restoration programs. S. cheilophila exhibited particularly noteworthy characteristics in promoting more uniform distribution of soil nutrients throughout the soil profile, which proved beneficial for comprehensive soil improvement and long-term ecosystem stability. This uniform nutrient distribution pattern suggests enhanced soil biological activity and improved nutrient cycling processes under this vegetation type. The comprehensive evaluation methodology, incorporating multiple soil quality indicators, yielded quantitative scores that clearly distinguished the restoration effectiveness of different species. S. cheilophila achieved the highest comprehensive evaluation score of 0.4570, while H. rhamnoides followed closely with a score of 0.4518, indicating both species' exceptional contribution to soil rehabilitation.

Conclusion Based on comprehensive soil characteristic analysis and comparative evaluation, this study recommends using S. cheilophila as one of the primary restoration species, followed by H. rhamnoides, to achieve better ecological restoration results.