A Study on Nitrogen Fixing Ability of Soil Isolates and Quantitative Estimation of K Solubilization by Soil and Plant Isolates

The aim of present investigation was to study the nitrogen fixing ability and quantitative estimation of K solubilization by soil isolates, plant and soil isolates respectively. Only JS series (JS1 to JS5) of soil isolates showed vigorous growth on N free media, hence tested for quantitative estimation of nitrogen fixing ability of the cultures by Acetylene reduction activity (ARA) assay out of five isolates tested, the highest ARA was recorded with JS1 (p<0.05; 47.08 nmole ethylene/mg cell protein/h) which was statistically at par with JS2 (p<0.05; 41.94 nmole ethylene/mg cell protein/h). Isolate JS5 showed the lowest Acetylene reduction activity which was statistically at par with JS3 and JS4. Quantitative estimation of potassium released from mica in broth revealed highest K release by MER 4 (p<0.05; 1.2 µg/ml broth) isolate followed by OS 10 (p<0.05; 0.9 µg/ml broth) which was statistically at par with JS5 (p<0.05; 0.8 µg/ml broth). JS4 and JS1could release 0.6 and 0.4 µg K/ml broth respectively and were statistically at par to each other. K released by isolate MER 3 was lowest (p<0.05; 0.2 µg/ml broth) and was at par with control.