Plant and soil properties mediate the response of soil microbial communities to moderate grazing in a semiarid grassland of northern China

Abstract

Even though a growing amount of information about the effects of livestock grazing on soil microbial communities have accumulated in literature, less is known about the combined response of plants, soil properties, and their interactions with soil microbes. In this study, we used a seven-year controlled grazing experiment to quantify the response of plant and soil properties and their interactions with soil microbial communities to moderate grazing in a semiarid grassland of Northern China. Our results showed that moderate grazing reduced the richness and diversity of soil microbial communities, as well as weakened community interactions. However, bacterial communities and their linkages were more stable under moderate grazing than fungal communities. Changes in aboveground plant biomass, soil water content, NO3−-N, and NO3/NH4 ratio dominated grazing effects on soil bacterial communities, while fungal communities were mainly influenced by plant N, soil NO3−-N, and NO3/NH4 ratio. Changes in the plant community composition played a key role in driving the composition of the fungal community. Our results provide a new insight into the response of soil microbes to moderate grazing, and suggest that above- and belowground communities should be considered to be precise indicators of the state and characteristics of the grassland ecosystem.