MAOM formation does not increase with more decomposers
We observed weak but significant negative correlations between the proportion of litter C in MAOM and microbial biomass (Fig. 6a , p<0.001). Root biomass was also negatively correlated with the proportion of litter C in MAOM (SI Fig. 5 ), but did not significantly alter native MAOM and did not covary with microbial biomass (SI Fig. 6 ). We also observed the destabilization of native MAOM after field incubation compared to the initial soil mixtures. Over the course of the growing season, we observed the loss of approximately 15% of native MAOM (Fig. 6b , p<0.10 for all soil types).