Yield and nutrients uptake of wheat (Triticum aestivum) and soil microbial parameters as influenced by plant-growth-promoting rhizobacteria

A field experiment was conducted at the ICAR-Indian Agricultural Research Institute, New Delhi, during the winter (rabi) season of 2014–15, to study the effect of 3 plant-growth-promoting rhizobacteria (PGPR) species, viz. PW5 (Providencia sp.), Azotobacter (IARI inoculant) and CW1 (Anabaena sp.), along with 75% recommended dose of nitrogen (N) and full dose of phosphorus (P) and potassium (K) fertilizers (N 150, P₂O₅ 60, K₂O 40) kg/ha on yield and nutrients uptake of wheat (Triticum aestivum L. emend. Fiori & Paol.), and on soil-microbial parameters. An increase of 22.6% in grain and 13% in straw yields was recorded in treatment receiving 75% N + Azotobacter + CW1 + PW5 over 75% N application. Microbial biomass carbon and dehydrogenase activity showed 12% and 37% increase with the application of 75% N + Azo. + CW1 + PW5 over recommended dose of NPK fertilizers, respectively. Further, protein content in grain and total nitrogen uptake were 34.5% and 16.4% higher in treatment receiving 75% N + Azotobacter + CW1 + PW5 than application of 75% N. Our results indicate that the combined application of either 2 or 3 species of bacterial inoculants with 75% N, on an average, saved 37.5 kg N/ha, and hence proved economical.