Isolation and characterization of mineral potassium solubilizing bacteria from rhizosphere soils

Abstract

Attempts were made to isolate potasium solubilizing bacteria (KSB) from rhizosphere soil of different crops in Nadia district of West Bengal. A total of ten bacteria isolates were tested for K solubilization and characterized up to genus level based on morphological and biochemical characters. Among the ten isolates, six were gram positive rods belonging to genera Bacillus and remaining four isolates was gram negative rod belonging to genera Pseudomonas. The mechanisms involved in K solubilization and other agronomical beneficial traits were also analyzed for selected efficient strains. The diameter of zone of solubilization formed by the isolates on agar media supplemented with mica at 1 per cent ranged from 0.60 to 1.26 cm at 72 hours after incubation. In vitro K solubilization from mica powder by bacteria ranged from 3.23?g/ml to 41.20?g/ml at 20 days after inoculation. Organic acids production by the KSB isolates is the main reason for solubilization of potassium from mica powder. Results further suggested that the use of efficient potassium mobilizers can be a feasible option for meeting the K-requirement of crops.