Influence of inceptisol and alfisol's Potassium Solubilizing Bacteria (KSB) isolates on release of K from waste mica

Abstract

Major part of potassium in soil exists in form of insoluble K-minerals. Fraction of Ksolubilized from such minerals through potassium solubilizing bacteria (KSB) will reduce cost on import of K- fertilizers. Nine and four isolates of K-solubilizing bacteria from Inceptisol (KI) and Alfisol (KA), respectively were evaluated for their ability to release of K from waste mica at 7, 14 and 21 days of incubation in modified Aleksandrov medium containing powdered waste mica as sole source of potassium. Morphological characteristics, zone of solubilization at week end and acidity of broth at different incubation periods were also studied. Majority of the isolates were entire smooth margin, raised, translucent, gram +ve rods and whitish to creamy in appearance. Isolates from cereals caused more zone of solubilization than pulse isolates. Isolates either from Alfisol or from Inceptisol efficiently decreased pH of the broth with increase in incubation periods. Isolates of same soil type differed in their K-release capacity. KSB isolates from Inceptisol showed higher K solubilization potential than isolates from Alfisol. Isolate KI1 & KA19 caused maximum acidity but lowest release of K from mica indicated that decrease in pH of the medium is not the only mechanism of K release from native K mineral of soil. Isolate KI16 and KA59 were high slime producer and showed highest 23.88 and 13.71 μg mL−1 K solubilization capacity, respectively and emerged out as potential isolates of Ksolubilizers as a K- biofertilizers.