Abstract: Soil bacteria, which have significant ecological functions in soil environment, play a very important role in soil biogeochemical processes. In this study, 454 pyrosequencing was applied to investigate the bacterial diversity of soil samples from rhizosphere (RS) and non-rhizosphere (NRS) in a continuous cropping poplar plantation (Populus×euramericana‘Neva’) in order to explore the soil bacterial community structure of poplar plantation and reveal the effects of continuous cropping on soil bacterial diversity. The results indicated that a total of 3036 operational taxonomic units (OTUs) were obtained from RS samples and 3051 from NRS samples, 1404 OTUs were shared by two groups of samples. The bacteria in soils from rhizosphere and non-rhizosphere belong to Acidobacteria, Actinobacteria, Armatimonadetes, Bacteroidetes, Chloroflexi, Gemmatimonadetes, Nitrospira, Planctomycetes, Proteobacteria, Firmicutes, TM7 and unclassified-bacteria, and the bacteria of Proteobacteria, Acidobacteria and Actinobacteria were the dominant groups. The indices of Chao1 and Shannon showed that continuous cropping descended the population diversities and enrichment of bacteria in soil samples from both rhizosphere and non-rhizosphere, and the descend intent was much higher in rhizosphere than in non-rhizosphere.

Key words: continuous cropping plantation, soil bacterial community diversity, 454 GS FLX, rhizosphere and non-rhizosphere