This study analyzed the characteristics of the soil bacterial community under different types of vegetation restoration, and explored the role of microorganisms in the vegetation restoration process, within the soil ecosystem of Grain for Green areas of the Loess Plateau. Typical artificial forest (artificial Robinia pseudoacacia forest, Pinus tabulaeformis forest), natural secondary forest, and grassland were selected as the research objects. High-throughput sequencing technology was used to analyze the α diversity and community structure of soil bacteria, and the correlation between soil environmental factors and bacterial communities. The Chinese National Ecosystem Research Network in Jixian County Station was chosen as the research area. The results showed that the bacterial communities of the five types of forest restoration comprised 25 phyla, 66 classes, 129 orders, 240 families, 392 genera, 760 species, and 2213 OTUs. There were significant differences in the abundance of bacterial communities, which could be ranked as follows: CD > CSL > CH2 > CH1 > YS. The dominant bacteria phyla in the different vegetation restoration types were Actinobacteria, Proteobacteria, Acidobacteria, and Chloroflexi. The relative abundances of natural secondary forest, grassland, and plantation were different, but not significantly. The relative abundances of α-Proteobacteria, β-Proteobacteria, and δ-Proteobacteria were higher in natural secondary forest soilthan in the soil of the other four restoration models, and the relative abundance was the lowest in grassland soil. The dominant bacteria were significantly correlated with soil pH and TN. Among them, TN was significantly positively correlated with Actinobacteria, pH was significantly positively correlated with Proteobacteria and negatively correlated with Actinobacteria, while Acidobacteria was significantly negatively correlated with soil pH and TN. PICRUSt analysis showed that the functional gene families were mainly related to 24 sub-functions, including cell motility, signal transduction mechanisms, amino acid transport and metabolism, as well as coenzyme transport and metabolism. These results can provide a good foundation for the evaluation of vegetation restoration in the Loess Plateau, as well as a scientific basis for the rational management of plantations.
Keywords: environmental factors; grain for green; high throughput sequencing; soil bacterial community; the Loess Plateau.