Effects of combined application of phosphorus and selenium on selenium absorption of winter wheat and microbial community in rhizosphere soil
The effects of combined application of phosphorus and selenium on the grain yield and microbial community structure and diversity in rhizosphere soil of winter wheat were studied to investigate the relationship between the microbial community and the effectiveness of phosphorus and selenium of winter wheat rhizosphere soil.A pot experiment with three phosphate levels(0,0.2 and 0.4 g·kg-1,respectively)and two selenium levels(0 and 0.5 mg·kg-1,respectively).A total of 6 treatments(termed as Se0P0,Se0P0.2,Se0P0.4,Se0.5P0,Se0.5P0.2 and Se0.5P0.4,respectively)were used to analyze their effects on the grain yield,phosphate and selenite concentration of winter wheat,soil available phosphate content,the transformation of chemical forms of selenite and microbial community structure.At Se0 and Se0.5,phosphate application significantly increased the grain yield of winter wheat,phosphate concentration and accumulation in each tissue,but significantly decreased selenite concentration in root,straw/leave and grain in Se0.5.While at Se0.5,the grain,glume and straw/leave selenite accumulation were firstly increased and then decreased with the increasing phosphate application,where the highest value appeared under the Se0.5P0.2 treatment.Selenite application significantly increased selenite concentration and accumulation in each tissue,decreased grain yield at P0.4 and phosphate concentration and accumulation in each tissue at P0.2 and P0.4,but had no significant effect on grain yield at P0.2.At Se0.5,phosphate application significantly increased available phosphorus concentration and the selenium concentration and proportion of soluble selenite in soil,and selenium application significantly increased available phosphorus concentration at P0.4.At Se0.5,P0.2 and P0.4 treatments significantly increased the relative abundance of Actinobacteria and Gemmatimonadetes,respectively,but significantly decreased the relative abundance of Bacteroides.Selenite application significantly increased the relative abundance of Actinobacteria at P0.2 and the relative abundance of Acidobacteria at P0.4.At Se0.5,compared with P0,P0.2 treatment significantly increased Shannon index.At P0.2,selenium application significantly increased Simpson index.Appropriate combined application of phosphate with selenium altered the microbial community structure,promoted the release of phosphate and selenite in soil and increased soil available phosphate and selenite content,enhanced the promoting effecting of phosphate on grain yield of winter wheat and the selenite accumulation of grain,the overall performance of at Se0.5P0.2 treatment was better than others.
phosphateselenitegrain yieldsoil available phosphorusselenium chemical forms transformationmicrobial community
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