Statistical analysis
To determine the extent to which ingrowth core treatments and
fertilization treatments altered the fate of litter C and N amendments,
we performed two-way analyses of variance in R version 3.5.1 (R Core
Team 2021). Model factors were ingrowth core treatment, fertilization
treatment, and their interaction. Post-hoc comparisons between groups
were made using the Tukey’s HSD test. Differences were considered
statistically significant at an alpha level of 0.05 (p<0.05)
and marginally significant at an alpha level of 0.10 (p<0.10).
Linear regression was used to investigate the effect of living roots or
microbial decomposers on litter C incorporation into MAOM. Outliers,
defined as samples where decomposer biomass was greater than 2 standard
deviations from the mean, were omitted from linear regression.