Impacts of Grazing Intensity and Plant Community Composition on Soil Bacterial Community Diversity in a Steppe Grassland

• Published in: PloS one 2016-07, Vol.11 (7), p.e0159680-e0159680
• Main Authors: Qu, Tong-Bao, Du, Wei-Chao, Yuan, Xia, Yang, Zhi-Ming, Liu, Dong-Bo, Wang, De-Li, Yu, Li-Jun
• Format: Article
• Language: English
• Subjects: Agricultural ecosystems; Analysis; Animals; Bacteria; Biodiversity; Biology and Life Sciences; Carbon; Communities; Community composition; Composition; Conductivity; Denaturing Gradient Gel Electrophoresis; Deoxyribonucleic acid; Diversity indices; DNA; Ecology; Ecology and Environmental Sciences; Ecosystem; Education; Electrical conductivity; Electrical resistivity; Environmental factors; Experiments; Fingerprinting; Flowers & plants; Gel electrophoresis; Grasses; Grasslands; Grazing; Grazing intensity; Herbivores; Horticulture; Laboratories; Legumes; Luminous intensity; Microbial colonies; Nitrogen; pH effects; Physiology; Plant communities; Plant diversity; Poaceae - microbiology; Polymerase Chain Reaction; Science; Sheep; Soil bacteria; Soil investigations; Soil Microbiology; Soil microorganisms; Soils; Steppes; Studies; Terrestrial ecosystems
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0159680

Soil bacteria play a key role in the ecological and evolutionary responses of agricultural ecosystems. Domestic herbivore grazing is known to influence soil bacterial community. However, the effects of grazing and its major driving factors on soil bacterial community remain unknown for different plant community compositions under increasing grazing intensity. Thus, to investigate soil bacterial community diversity under five plant community compositions (Grass; Leymus chinensis; Forb; L. chinensis & Forb; and Legume), we performed a four-year field experiment with different grazing intensity treatments (no grazing; light grazing, 4 sheep·ha-1; and heavy grazing, 6 sheep·ha-1) in a grassland in China. Total DNA was obtained from soil samples collected from the plots in August, and polymerase chain reaction (PCR) analysis and denaturing gradient gel electrophoresis (DGGE) fingerprinting were used to investigate soil bacterial community. The results showed that light grazing significantly increased indices of soil bacterial community diversity for the Forb and Legume groups but not the Grass and L. chinensis groups. Heavy grazing significantly reduced these soil bacterial diversity indices, except for the Pielou evenness index in the Legume group. Further analyses revealed that the soil N/P ratio, electrical conductivity (EC), total nitrogen (TN) and pH were the major environmental factors affecting the soil bacterial community. Our study suggests that the soil bacterial community diversity was influenced by grazing intensity and plant community composition in a meadow steppe. The present study provides a baseline assessment of the soil bacterial community diversity in a temperate meadow steppe.