2.6 Statistical analysis
All statistical analyses were performed by R software. Pearson
correlation analysis was applied to explore relationships between SOC,
DOC, and environmental factors, including pH, SWC, BW, nutrients, and
microorganisms. Analysis of variance (ANOVA) isĀ used to compare
differences among different treatments. Principle component and multiple
linear regression analyses using the stepwise regression method were
carried out to decipher potential links and predominant factors that
affected SOC and DOC change. Considering environment factors were
closely and intercorrelated, a partial least square path model (plspm)
was used to explore and visualize effects of which ecological process or
components on SOC and DOC before and after biochar amendment (Brown and
Human, 1997). The plspm R package can be download at
https://cran.r-project.org/src/contrib/Archive/plspm/.