Potential for Biochar as an Alternate Carrier to Peat Moss for the Preparation of Rhizobia Bio Inoculum

Abstract

Carrier based preparations of Rizobium  inoculant, developed using two different rice biochar preparations  (biochar alone and biochar- vermiculite 50:50 ) were evaluated in comparison with peatmoss based carrier (peatmoss: vermiculite 50:50) for their suitability as a best alternate of peatmoss for commercial production of Rizobia. The three different carriers were evaluated over a period of 180 days for its moisture content, pH, survival of the microbial inoculant and respiration rate. At the end of storing period (180 days) different carrier materials were used to inoculate kidney bean seeds in a pot experiment conducted in sandy soil to ensure the viability of survived Rizobia in different carrier preparations. In addition, the ability of carrier materials to ameliorate the antimicrobial effect of seed diffusate was also assessed. Among the different carriers, bio char based carrier recorded a maximum population of log 9.98 cfu g–1 of carrier on 180 days after inoculation with a maximum moisture content of 20%. A slight decline in pH was recorded at the end of storing period.  It was also found that kidney bean seeds inoculated with bio char based inoculant gave the highest nodule dry weight, plant dry weight, plant height. In addition, biochar was found to ameliorate the antimicrobial effect of kidney bean seed diffusate.