2.6 | Data processing
The similarities and differences between the samples were based on
operational taxonomic unit (OTU) clustering, and representative
sequences in the OTU clusters were obtained. The most abundant sequences
were selected as representative OTUs and used in various OTU analyses.
The soil bacteria alpha diversity was calculated after randomly
subsampling sequences to an equal number. Four metrics were used for
alpha diversity analysis, namely the observed species richness (Chao)
index, abundance-based coverage estimator (ACE) index, Shannon index,
and Simpson’s index (Prober et al., 2015; Gao et al., 2018). To analyze
the species turnover, we calculated the Bray–Curtis dissimilarity for
the same subplot with different forest types, slope positions, and
depths. Principal coordinate analysis (PCoA) of the β-diversity was
calculated based on the Bray–Curtis algorithm. The structure equation
model (SEM) was used to assess the direct effects of planting G.
jasminoides in C. oleifera on soil physicochemical properties
and soil bacterial characteristics (He et al., 2020).The data were
analyzed using the free online Majorbio Cloud Platform
(www.majorbio.com). Statistical differences were tested by ANOVA.