the effect of plant growth promoting rhizobacteria, nitrogen and phosphorus on relative agronomic efficiency of fertilizers, growth parameters and yield of wheat (triticum aestivum l.) cultivar n-80-19 in sari

in order to evaluate the efficiency of plant growth promoting rhizobacteria (pgpr) plus nitrogen and phosphorous chemical fertilizers on relative agronomic efficiency of p and n fertilizers and some agronomic parameters of wheat (triticum aestivum l.) cultivar n-80-19, an experiment was conducted at sari agricultural sciences and natural resources university during growing season of 2008-2009. experiment was arranged in split-split plot based on randomized complete block design with three levels (0, 25 and 50 kg.ha-1) and sub-plots were considered pgpr at four levels (control, inoculation with nitrogen fixing bacteria (pfb), phosphate solubilizing bacteria (psb) and dual inoculation with pfb and psb) with three replications. results showed that the application of biofertilizers significantly increased relative agronomic efficiency of n and p fertilizers, spike number, plant height, flag leaf area, grain yield and grain weight of wheat. application of biofertilizers increased wheat grain yield as much as 46.6% as compared to control. double inoculation of biofertilizers improved relative agronomic efficiency of fertilizers by 58.4 and 76.5% as compared to control, respectively. integrated treatments showed higher performance compared to separate treatments. generally, biofertilizers with low levels of p and n fertilizers significantly improved yield components of wheat without any reduction in yield related parameters.