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.