nitrogen and phosphorus use efficiency of spring wheat (triticum aestivum l.) as affected by seed inoculation with plant growth promoting rhizobacteria (pgpr)

in order to study of the effect of seed inoculation with pgpr on nitrogen and phosphorus use efficiency of spring wheat in different levels of nitrogen and phosphorus fertilizers, an experimental was conducted at the research farm of mohageh ardabili university, ardabil, iran during 2012 year. the combination of nitrogen fertilizer in three levels (0, 40 and 80 kg n/ha as urea) and phosphorus fertilizer (0, 30 and 60 kg p2o5/ha) were factorally assigned to the main plots and seed inoculation with plant growth promoting rhizobacteria in three levels (no inoculation, seed inoculation with azotobacter chorchorum strain 5 and azosprilium lipoferum strain of) were assigned to the subplots. the results showed that maximum nitrogen use efficiency was obtained at highest level of phosphorus, control level of nitrogen and seed inoculation with azospirillum. maximum of phosphorus use efficiency was obtained at highest level of nitrogen, control level of phosphorus and seed inoculation with azospirillum. while minimum of this trait was observed at highest level of phosphorus and control level of nitrogen and pgpr. also results showed that, root weight, root length, grain yield and biological yield were significantly affected by experimental treatments. maximum root weight and root length were obtained in the plats which were applied highest rates of nitrogen, phosphor fertilizer and seed inoculation with azotobacter and minimum of they were obtained in no application of them. maximum of grain yield and biological yield were obtained in the plots which was applied the highest rates of nitrogen and phosphor fertilizers in seed inoculation with azosprilium and minimum of they were obtained in no application of them.