Characterization of Phosphate Solubilizing and Potassium Decomposing Strains and Study on their Effects on Tomato Cultivation

Seven strains were collected for phosphate solubilizing and potassium decomposing activities from Microbiology Laboratory, Department of Biotechnology, Shweziwa Biofertilizer Plant. When phosphate solubilizing activity of selected strains was qualitatively determined, all strains except from B1 strain, gave clear zone formation on NBRIP media. But when quantitatively determined by spectrophotometric method, all strains solubilized insoluble tricalcium phosphate. Among seven strains, Ps strain gave the highest soluble phosphate concentration (386 ppm). Potassium decomposing activity was also determined for qualitatively and quantitatively. For qualitative determination, potassium decomposing activity was screened for clear zone formation on potassium decomposing media. Among seven strains, B1 and Y strains cannot give clear zone around their colonies. But when determined by AAS method, all strains can decompose potassium mica by giving soluble potassium concentration. Y strain gave the highest soluble potassium concentration (8.45 ppm). Phosphate solubilizing and potassium decomposing strains were combined differently for four treatments to study their effects on tomato cultivation. Chemical fertilizer was also applied to compare with selected strains. Among all treatments, T-4 showed better result on total yield although yields were not significantly different.