Influence of Plant Growth-Promoting Rhizobacteria on Corn Growth Under Different Fertility Sources

A greenhouse study was conducted to evaluate the effects of plant growth-promoting rhizobacteria (PGPR) on root establishment and biomass production of corn (Zea mays L.) using three fertility sources (poultry litter (PL), biosolids, and urea). Applying PL significantly improved root morphological parameters and increased plant biomass at the V4, V6, and VT growth stages when compared to the other fertility sources. At the V4 stage, PGPR stimulated root growth and enhanced aboveground biomass with urea and PL, while no differences were observed with biosolids. At the V6 stage, PL, biosolids, and urea with PGPR significantly increased some growth parameters (e.g., plant height, leaf area, and root morphology). However, at the VT stage, PGPR's influence on plant growth was minimal regardless of fertility source. Applying the fertility sources at 135 kg N ha(-1) may have masked PGPR's influence on corn growth as the plants reached their later vegetative growth stages.