Changes in rhizosphere microbial community structure in response to reclaimed water irrigation

Limited water resources in Beijing have created much interest on the part of municipalities to utilize nonpotable waters in urban areas. For/ understanding the microbial community structure in response to irrigation with reclaimed water and assessing the feasibility of using the reclaimed water as an alternative irrigation source for lawn in Beijing, a investigation was conducted on the changes of distribution of soil rhizosphere microbe, in the lawn soil irrigated with reclaimed water. Soil samples were directly plated on corresponding isolation mediums. Single colony isolates from different media were counted. The culturable heterotrophic bacterial diversity was investigated by amplified rDNA restriction analysis (ARDRA).Comparison of the restriction fragment length polymorphism of isolates from each soil suggested that the RW irrigation increased the bacterial diversity. There were 52 operational taxonomic units (OTUs) in the RW-irrigated library, whereas only 38 in the control, an increase of 36.8%. While the RW-irrigated library had 63.5% rare OTUs and 1.9% the most abundant OTUs the control had 57.9% and 7.9% respectively. The increase in diversity was accompanied by an increase in evenness.