Development and Evaluation of a Microbial Consortium for enhancing Fertility and Productivity in Saline Soil

Plant growth promoting rhizobacteria (PGPR) is a group of stress tolerant bacteria which possess unique properties that help in plant growth promotion under environmental stress conditions. These bacteria are promosing alternatives to chemical fertilizers and can be extensively used in organic farming. In this study, halotolerant microorganisms isolated from saline agricultural soil collected from Patharvala, Maharashtra have been investigated for their plant growth promoting ability. The isolates were qualitatively and quantitatively analzed for their plant growth promoting traits such as nitrogenase activity, IAA production potential, ability of phosphate solubilization, siderophore production using Ashby’s nitrogen free medium, yeast malt dextrose medium, Pikovaskaya’s medium and King’s B medium respectively. Salkowski’s method for quantification of the produced IAA yielded highest concentration of 6.10 mg/ml. Siderophore production potential of the isolates was analyzed using CAS reagent and quantified with the maxima of 12.86 PSU. Initially, 76 halotolerant bacteria were isolated from saline soil, out of which three isolates belonging to the genus Azotobacter were selected based on their highest PGPR activity and used for the preparation of inoculum for seed germination assay. The germination rates of black eyed beans seeds with consortium, commercial biofertilizer and control were calculated as 87.5%, 90.9% and 69.6% respectively, confirming the effectiveness of the bacterial consortium and commercial biofertilizer for improving seed germination compared to control in salt stress conditions.