Changes in litter quality induced by N deposition alter soil microbial communities
Abstract Soil microbial community composition and litter quality are important drivers of litter decomposition, but how litter quality influences the soil microbial composition largely remains unknown. We conducted a microcosm experiment to examine the effects of changes in litter quality induced by long term N deposition on soil microbial community composition. Mixed species litter and single species litter were collected from a field experiment with replicate plots exposed to long term N addition in a semiarid grassland in northern China. The litters were decomposed in a standard live soil after which the composition of the microbial community was determined by Illumina MiSeq Sequencing. Changes in litter stoichiometry induced by N addition increased the diversity of the fungal community. The alpha diversity of the fungal community was more sensitive to the type of litter (mixed or single species) than to the N addition effects, with higher abundance of fungal OTUs and Shannon diversity observed in soil with mixed species litter. Moreover, the relative abundance of saprophytic fungi increased with increasing N addition rates, which suggests that fungi play an important role in the initial stages of the decomposition process. Litter type and N addition did not significantly change the diversity of bacterial community. The relative abundance of ammonia oxidizing bacteria was lower in high N addition treatments than in those with lower N input, indicating that changes in litter stoichiometry could change ecosystem functioning via its effects on bacteria. Our results presented robust evidence for the plant mediated pathways through which N deposition affects the soil microbial community and biogeochemical cycling.
Soil Biology and Biochemistry