Research on the Microecological Mechanisms of Different Native Tree Species in Ameliorating Rocky Desertification Soils

This study investigated the effects of different native tree species on soil physicochemical properties, understory vegetation diversity, and the structure and diversity of soil microbial communities in rocky desertification areas. By combining soil physicochemical analysis with high-throughput sequencing technology, systematic comparisons were made of the understory vegetation composition, soil physicochemical indicators, and microbial communities among the tree species. The results showed that: (1) Significant differences were observed in understory vegetation diversity and soil physicochemical properties across the different native tree species. Vegetation diversity ranked as follows: Metasequoia glyptostroboides > Cornus wilsoniana > unplanted grassland > Nyssa sinensis > Michelia maudiae. Soil bulk density, porosity, and water content were significantly lower in M. glyptostroboides stands than under other species. Soil organic matter content was highest in M. glyptostroboides stands, while nitrogen and phosphorus contents were higher in M. maudiae stands. Soil pH was significantly higher in C. wilsoniana stands, and potassium content was highest in unplanted grassland. (2) Soil microbial community diversity and composition also varied significantly among tree species. Fungal diversity ranked as: M. glyptostroboides > N. sinensis > unplanted grassland > M. maudiae > C. wilsoniana; bacterial diversity followed: M. glyptostroboides > C. wilsoniana > N. sinensis M. maudiae unplanted grassland. Agaricales were the dominant fungal group in M. maudiae soil, whereas Hypocreales and Mortierellales were predominant in M. glyptostroboides soil. The abundance of Chloroflexi was significantly higher in N. sinensis soil than in other plots. (3) Soil microbial community structure and diversity were closely correlated with understory vegetation abundance, soil bulk density, nitrogen and phosphorus content, and pH. In fungal communities, Basidiomycota were influenced by pH and vegetation diversity, while Ascomycota and Mortierellomycota were affected by nitrogen content and bulk density, respectively. In bacterial communities, Chloroflexi, Myxococcota, and Actinobacteriota were significantly influenced by pH; Chloroflexi and Verrucomicrobiota were markedly affected by nitrogen forms; available phosphorus had significant effects on Chloroflexi, Myxococcota, and Actinobacteriota; and vegetation diversity significantly influenced Verrucomicrobiota, Acidobacteriota, and Myxococcota