Grassland use impacts on soil properties and microbial communities: A
case study from the Qinghai-Tibetan plateau
Abstract
Different grazing practices can have varying impacts on soil properties
and soil microbial communities, which are critical for maintaining
productivity and functions of grasslands and the overall ecosystem. The
Qinghai-Tibetan plateau (QTP) is the largest high-altitude grazing
region on earth, and has three different grazing practices, including
seasonal grazing (SG), continuous grazing (CG), and exclosure grazing
(EG) for 10 years. Vegetation, soil properties from two different depths
(0-0.15 and 0.15-0.30 m) and soil microbial communitiesin the surface
soil layer (0-0.15 m) were measured in triplicate plots within each
grazing practice. The soil conditions in the SG site were the best, the
CG site was the worst, while the EG site was intermediate. Dry
aboveground biomass, soil organic carbon, total nitrogen, and total
phosphorus content under SG were 838 g/m2, 20.73g/kg, 1.74 g/kg, and
0.20 g/kg, respectively, and under CG were 8.80 g/m2, 8.07g/kg, 1.07
g/kg, 0.16 g/kg, respectively. There was no significant difference in
the α-diversity of soil bacteria and fungi among the three grazing
practices. However, the bacterial communities were significantly
different from each other; only the fungal community under EG was
significantly different from the other grazing practices. While the
relative abundance of Basidiomycota under SG was significantly higher
than that under EG, no difference was observed in the relative abundance
of Ascomycota, Zygomycota, and unclassified_k_Fungi among the three
grazing practices. Compared to SG, CG and EG significantly increased the
relative abundance of Actinobacteria, Gemmatimonadetes, Verrucomicrobia,
and Nitrospirae, but decreased the relative abundance of Proteobacteria
and Bacteroidetes.