Bacteria are widely distributed and play an important role in soil carbon (C) cycling. The impact of soil bacterial diversity on soil C storage has been well established, yet little is known about the underlying mechanisms and the interactions among them. Here, we examined the association between soil bacterial diversity and soil C storage in relation to vegetation restoration on the Loess Plateau. The dominant phyla among land use types (artificial forest, Af; natural shrubland, Ns; artificial grassland, Ag; natural grassland, Ng; slope cropland, Sc) were Acidobacteria, Actinobacteria, Alphaproteobacteria, and Betaproteobacteria, which transited from Acidobacteria-dominant to Actinobacteria-dominant community due to vegetation restoration. Soil C storage and the Shannon diversity index of soil bacterial community (HBacteria) showed the order Ns > Ng > Af > Ag > Sc, whereas no significant difference was found in Good's coverage (p > .05). Further, a strong relationship was observed between the relative abundance of dominant bacterial groups and soil C storage (p < .05). Additionally, soil bacterial diversity was closely related to soil C storage based on the structural equation model (SEM) and generalized additive models (GAMs). Specifically, soil C storage had the largest deterministic effects, explaining >70% of the variation and suggesting a strong association between soil C storage and soil bacterial diversity. Overall, we propose that further studies are necessary with a focus on the soil bacterial groups with specific functions in relation to soil C storage on the Loess Plateau.
Keywords: High-throughput sequencing; Land use types; Loess Plateau; Soil C storage; Soil bacterial diversity.
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