Evaluation of Plant Growth-Promoting Rhizobacteria on Stockpiled Bermudagrass
Type of DegreeMaster's Thesis
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A two-year, small-plot study was conducted to evaluate plant growth-promoting rhizobacteria (PGPR) as an alternative form of N fertilization for fall-stockpiled bermudagrass. Eighteen 1-m2 Coastal bermudagrass plots were mowed to a 2.5-cm stubble height prior to stockpiling. Experimental treatments included a negative control, synthetic fertilizer, DH44, DH44 + fertilizer, Blend 20, and Blend 20 + fertilizer (n = 3). Two applications of PGPR were applied at the beginning of each stockpiling season in August and again 30 d later. Ammonium sulfate was applied at a rate of 56 kg N ha-1 concurrent with the first PGPR application. One-third of each plot was clipped to a height of 2.5 cm in mid-November, December, and January of each year to determine forage dry matter (DM) yield and nutritive value. Forage DM yield was greatest for Blend 20 + fertilizer, but it was not different (P = 0.2552) from that of the synthetic fertilizer treatment. Concentration of CP was least (P 0.0437) for DH44 and Blend 20 treatments. Concentrations of NDF and ADF were similar among all treatments, except for the negative control. In vitro true digestibility was not different (P < 0.05) among treatments. Yield and nutritive value parameters were greater in Year 2 than Year 1. These results indicate that PGPR are a viable option for biofertilization; however, further investigation into the effect of PGPR inoculants on a larger scale is needed.