Use of Plant-Growth-Promoting Rhizobacteria (PGPR) Seed Inoculation as Alternative Fertilizer Inputs in Wheat and Barley Production

In this study we aimed to investigate the effects of plant-growth-promoting rhizobacteria (PGPR) on seed incubation of spring wheat and barley. Three bacterial strains were applied singly and in combinations. Seed inoculation with strains significantly affected grain yield (GY), straw (SWY), total yield (TY), and plant nutrient element (PNE) content. In field trials, compared to the control, single inoculations gave GY SWY, and TY increases by 27.5-31.9%, 1.1-5.3%, and 1.3-11.3% in wheat and 15.1-27.8%, 10.8-15.5%, and 14.5-18.5% in barley, respectively, but mixtures of strains gave increases in GY, SWY, and TY by 54.7%, 2.1%, and 6.7% in wheat and 57.8%, 14.6%, and 17.5% in barley, respectively. According to the results, it was concluded that seed inoculations with PGPR and mixture inoculation might satisfy nitrogen requirements, but Bacillus megaterium M3 and MIX (Bacillus subtilis 05U142, B. megaterium M3, Azospirillum brasilense Sp245) inoculation provided greater PNE concentrations than mineral fertilizer application for wheat and barley under field conditions.