| Abstract:In order to investigate the effect of nitrogen addition on soil bacterial community structure and diversity,an insitu nitrogen addition experiment was conducted in an alpine swamp meadow of Qinghai-Tibet Plateau.Three nitrogen treatments(CK,0 g·m-2·a-1; N1,5 g·m-2·a-1; N2,10 g·m-2·a-1) was set,the soil samples were collected from the 0-10 cm,10-20 cm and 20-30 cm soil layers,based on high-throughput sequencing technology,combined with soil physicochemical properties and determination of the microbial biomass carbon and nitrogen,the change of soil bacterial community structure was studied under different treatments of nitrogen addition.The results showed that five dominant bacterial phyla were Proteobacteria,Acidobacteria,Actinobacteria,Gemmatimonadetes and Firmicutes,the effect of nitrogen addition on the relative abundance of different bacterial groups was different atdiffrent soil layers. With increasing nitrogen application,the bacterial diversity indexes had declining tend,but the overall difference was not significant. The correlation analysis showed that there were significant positive relations between ammonium nitrogen and Ace index,Chao1 index and Shannon index; nitrate nitrogen,soil organic carbon and soil water content were significantly correlated with specific bacteria at phylum level. The results showed that increasing nitrogen deposition in alpine swamp meadow on the Qinghai-Tibet Plateau can affect the composition of soil bacterial community and inhibit bacterial diversity. In addition,soil ammonium nitrogen,nitrate nitrogen,organic carbon and water content are key factors affecting soil bacterial community under different treatments of nitrogen addition. |
