Influence of plant growth-promoting rhizobacteria on corn growth under different fertility sources

Authors: LIN, YARU - Auburn University; Watts, Dexter; KLOEPPER, JOSEPH - Auburn University; Torbert, Henry - Allen

Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/16/2018
Publication Date: 4/13/2018
Citation: Lin, Y., Watts, D.B., Kloepper, J.W., Torbert III, H.A. 2018. Influence of plant growth-promoting rhizobacteria on corn growth under different fertility sources. Communications in Soil Science and Plant Analysis. 49:1239-1255. https://doi.org/10.1080/00103624.2018.1457155.
DOI: https://doi.org/10.1080/00103624.2018.1457155

Interpretive Summary: There are free-living bacteria in soil that live around the plant roots. Previous research has shown that some of these bacteria can improve plant growth by increasing the supply or availability of soil nutrients for plant uptake. These bacteria are called plant growth-promoting rhizobacteria (PGPR). A greenhouse container study was conducted to determine the influence of PGPR application along with poultry litter and biosolids on corn growth. The use of PGPR resulted in some differences for the plant growth parameters, but no consistent increase in corn biomass production was observed. However, since all fertilizer sources (poultry litter, biosolids, and urea) were applied at the optimal rate needed to maximize corn production the impact of the PGPR on plant growth-promotion may have been masked.

Technical Abstract: Free-living bacteria in the plant rhizosphere can mediate soil processes such as nitrogen fixation, mineralization, solubilization, and nutrient mobilization. Thus, inoculating seeds with bacteria known to promote plant growth may be a promising technique for enhancing nutrient-use efficiency and improving crop production. Accordingly, a study was conducted to evaluate the effects of plant growth-promoting rhizobacteria (PGPR) on root establishment and biomass production of corn (Zea mays L.) during the early growth stages using three fertility sources under greenhouse conditions. Treatments included three fertility sources (poultry litter (PL), biosolids, and urea) at 168 kg total N ha-1 and five PGPR inoculants (4 PGPR strain mixtures and 1 control without PGPR). 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 PGPR and 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. Future research is needed to evaluate the influence of PGPR on plant growth when fertility requirements are not optimal.