The effect of plant growth promoting bacteria inoculated in soil and different rates of phosphorous fertilizer on growth and yield of autumn wheat

Recently, growth-promoting bacteria have been proposed as complementary and increased efficiency of chemical fertilizers in order to increase soil fertility in crop production in sustainable agriculture. In order to study the effect and efficacy of plant growth promoting bacteria and different rates of phosphorous fertilizer on growth parameters, nutrient availability and wheat yield (Mahdavi variety), a field experiment was conducted as factorial based on completely randomized block design in three replications. Experimental factors include five rates of phosphorous (0, 25, 50, 75, and 100 kg/ha P) and soil inoculation with bacteria at four levels including no-inoculation (Control, I0), inoculation with Azotobacter (I1), inoculation with Pseudomonas (I2) and inoculation with Azotobacter and Pseudomonas (I3). Results of variance analysis showed a significant difference on the effect of seed inoculation and phosphorous levels on plant height, root length and germination percent of wheat seeds. In this research, the treatment of 100 percent P-requirement in the soil inoculated with Azotobacter and Pseudomonas showed a greatest effect on increasing soil phosphorous (27%), growth (28%), yield (27%), yield components (31% grain yiehd) and grain phosphorous (27%) of autumn wheat. Increase in plant dry weight by rhizobacteria is due to increase in nutrients uptake and subsequently better plant growth which could result in higher harvesting index.