The study evaluated five different carrier formulations: pure diatomaceous earth, diatomaceous earth with charcoal (8:2), pure decomposed coir waste, diatomaceous earth with decomposed coir waste (6:2) and lignite. The effectiveness of the alternate carrier material was studied with one of the nitrogen-fixing microorganism Rhizobium leguminosarum. Its efficacies in plant growth were tested with three different leguminous seeds like horse gram, black gram, and chickpea. In parallel, the microbial sustenance of all the inoculums was monitored by frequent serial dilution and plating techniques. The nitrogenase activities of the carrier inoculum as well as the treated soil were tested by gas chromatography after 60 days.
The combination of diatomaceous earth with charcoal in the ratio of (8:2) was found to be very highly competent for Rhizobium. It is closely followed by pure decomposed coir waste which gave highly satisfactory results in accordance with the former combination. The combination of diatomaceous earth with charcoal had shown 177.66 CFU, which was relatively more than that of the other tried carrier material, i.e., lignite with 135 CFU and pure diatomaceous earth had shown 88.33 CFU which is least of all the carrier combination. The nitrogenase activity was observed better in the combination of diatomaceous earth with charcoal carrier-based biofertilizer which was found to be 13.38 nmol whereas that of the lignite carrier-based biofertilizer was found to be 8.37 nmol. The pure coir had given relatively better result in nitrogenase activity, i.e., about 5.851 nmol. |
