Vol. 9, Special Issue 12, Part L (2025)

The current investigation entitled “Isolation and Characterization of Nitrogen Fixing Phosphate and Potash Solubilizing Bacteria and Their Inoculation Effect on Sorghum” was carried out as field experiment during the Rabi 2024 at farm of the Department of Plant Pathology and Microbiology, Mahatma Phule Krishi Vidyapeeth, Rahuri. The rhizospheric soil samples of orchards of Mango, Tamrind, Fig, Coconut and Sapota were collected for isolation of nitrogen fixer, PSB and KSB. Out of these collected samples seven isolates of nitrogen fixer designated as MRN-1, MRN-2, TRN-1, FRN-1, CRN-1, CRN-2 and SRN-1; four isolates for P -solubilizing such as MRP-1, TRP-1, TRP-2 and SRP-1 and 3 isolates for K solubilizing bacteria named as TRK-1, SRK-1and SRK-2 were isolated by serial dilution and pour plate method. Ashby’s, Pikovaskya’s and Aleksandrow’s media were used for isolation of nitrogen fixing, Phosphate solubilizing bacteria and Potash solubilizing bacteria, respectively. These isolates undertook laboratory testing to determine their efficacy. On the basis of test results isolates were identified as Azotobacter spp., Bacillus spp. and Pseudomonas spp. and used for further field experimental studies.

Among all treatments, Azotobacter spp. (Nitrogen fixer), Bacillus spp. (PSB) and Pseudomonas spp. (KSB) along with 100% RDF found to be highly significant which increased germination percentage (94.03), plant height (236.70 cm at flowering and 241.33 cm at harvesting), number of leaves (14.33), root length (13.33 cm), Panicle length and girth (23.17 cm and 16.67 cm), 1000 grain weight (34.57 g), grain and fodder yield (27.70 and 55.40 q ha^-1). While among all treatments there was non-significant differences were observed as regards number of days required for 50% flowering of sorghum. However, the application of 75% RDF + Azotobacter, PSB and KSB was found to be statistically at par with 100% RDF + Azotobacter, PSB and KSB. From present investigation on the basis of it was concluded that, the seed treatment of Azotobacter, PSB and KSB with 75% RDF found to be effective. As this treatment saves the 25% of dose of nitrogen, phosphate and potash fertilizer to obtained maximum growth and yield of Sorghum.