INTEGRATED TREE–SHRUB–GRASS VEGETATION RESTORATION IN SANDY RIPARIAN ZONES OF THE YARLUNG TSANGPO RIVER: TECHNIQUES AND ECOLOGICAL IMPLICATIONS

Abstract To advance the theory and practice of vegetation restoration on desertified lands, we conducted a field-based investigation in the sand-control experimental zone of lirong Township, Milin County, situated in the middle reaches of the Yarlung Tsangpo River. Through a combination of long-term fixed-point observation and controlled field experiments, we examined the ecological impacts of integrating tree-shrub-grass species. We developed a composite planting model suited for sandy riparian zones and evaluated its performance. Results demonstrate that such vegetation assemblages effectively reduce wind speed, enhance relative humidity, and stabilize air, surface, and subsurface temperatures. Furthermore, the treatments improved soil water content and porosity while reducing bulk density and pH. Soil fertility metrics—including organic matter, total nitrogen, phosphorus, and potassium—also showed significant improvement, enhancing the land’s productivity. Among the tested configurations, the assemblage of Cupressus gigantea, Sophora moorcroftiana, Medicago sativa, Melilotus officinalis, Eragrostis nigra, and Astragalus adsurgens, when paired with rainwater-collecting trays and geocell structures, proved optimal for ecological restoration in the riparian sandy soils of the central Yarlung Tsangpo basin.