## 3 Results Analysis
### Analysis of Soil Microbial Diversity and Community Structure  
The Venn diagram (Figure 4) shows that more than 3170 OTUs were detected in total in the soil samples of the five treatments in this study, of which the total number of OTUs was higher, reaching 3110. The Coverage index value of each sample was above 97%, and the sequencing results could accurately reflect the biological characteristics of the samples. Figure 3: Soil enzyme activities in different restoration patterns. (**a**) catalase, (**b**) urease, (**c**) phosphatase, (**d**) sucrase, (**e**) BG enzyme, and (**f**) NAG enzyme. Note: Letters represent significant differences between different soil layers in the same stand (\(p<0.05\)). In addition, Table 3 shows the species diversity index of different forest restoration modes. Among them, the Shannon index and Simpson diversity index were basically similar under different restoration modes. However, the Chao1 index varied greatly, especially in the AR&AM&MS treatment. Furthermore, the horizontal species distribution histograms under different ecological forest restoration modes, as shown in Figure 5, can visually show that the species composition and proportion of the five treatments are very similar. It can be seen from the relative abundance of species (Figure 5a) that the relative proportion of bacteria in all treatments in this study is above 99.8%. At the phylum level (Figure 5b), it can be seen that the dominant bacterial groups in soil microorganisms include _Proteobacteria_ (about 38%), _Aciobacteria_ (about 23%), _Actinobacteria_ (about 11%), _Bacteroidetes_ (about 6%), and _Gemmatimonadetes_ (about 5%). Also, at the class level in Figure 5c, it can be seen that the five treatments in this study were most abundant in terms of _Alphaproteobacteria_ (about 18%), _Betaproteobacteria_ (about 8%), and _Actinobacteria_ (about 5%). At the order level, as shown in Figure 5d, the five treatments in this study had the highest levels of _Sphingomonadales_ (about 12%), _Rhizobiales_ (about 8%), _Burkholderiales_ (about 5%), and _Xanthomonadales_ (about 4%). Based on the species annotation and abundance information at the genus level for all soil samples, the genera with the top abundance rankings were selected in Figure 6. Using the abundance information for clustering, the results show that the microbial community structures under the four restoration mode species are significantly different. They  
Figure 4: Venn diagram of the number of operable taxonomic units (OTUs) for different restoration modes. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Treatment**} & \multicolumn{2}{c}{**Observed OTUs 97\%**} & \multicolumn{2}{c}{**Chao1 Index**} & \multicolumn{2}{c}{**Simpson Index**} & \multicolumn{2}{c}{**Shannon Index**} \\  & **Average** & **Error** & **Average** & **Error** & **Average** & **Error** & **Average** & **Error** \\ \hline AR & 3153 & 6 & 3114.84 & 9.96 & 0.96 & 0.0002 & 4.82 & 0.0051 \\ AM & 3159 & 20 & 3116.50 & 19.08 & 0.96 & 0.0001 & 4.82 & 0.0024 \\ MS & 3155 & 8 & 3119.60 & 1  
are mainly divided into two categories, with AM and AR&AM&MS being more abundant. The main genus-level microorganisms include _Solrubrobacter_, _Giaella_, _Sphingsiniella_, _Bradynhizobium_, _Lysobacter_, _Phenylobacterium_, _Sphingomonas_, _Steroidobacter_, _Streptomyces_, and _Variovorax_. Furthermore, Figure 7 analyzes the beta diversity of species under different forest restoration modes. Figure 7a uses the PCA model. The closer the two samples are to the PCA, the more similar the species composition of the two samples. As can be seen, the AL and MS treatments are close together, indicating that their compositions are similar, which is similar to the analysis results in Section 3.1. In addition, the AR and AR&AM&MS treatments have similar compositions. Figure 7b employs principal coordinates analysis (PCoA), a dimensionality reduction method similar to PCA. This means that AR and AM are most similar and that the species diversity processed by AR&AM&MS is richer.