Experimental design
We incubated isotopically enriched litter in soil ingrowth cores and
traced the fate of litter C and N into SOM over one growing season. Our
experimental design included 3 levels of root/hyphal ingrowth (root and
fungal ingrowth, root exclusion and fungal ingrowth, and root and fungal
exclusion) and 3 fertilization treatments (no fertilization, high-level
inorganic fertilization, or organic fertilization). We randomly selected
5 plots from each fertilization treatment from those which had
successful rhizome establishment during initial plot development. Within
each plot, we replicated each ingrowth core treatment twice, resulting 6
cores per plot (SI Fig. 2b ). This resulted in a total of 90
experimental ingrowth cores (3 cores x 3 fertilization treatments x 5
plots x 2 plants/plot).