Abstract
A hydroponics study was carried out to evaluate the effect of three plant growth promoting rhizobacteria (PGPR) namely, Bacillus mucilaginosus, Azotobacter chroococcum, and Rhizobium spp. on their ability to mobilize potassium from waste mica using maize and wheat as the test crops under a phytotron growth chamber. Results revealed that PGPR significantly improved the assimilation of potassium by both maize and wheat, where waste mica was the sole source of potassium. This was translated into higher biomass accumulation, potassium content and uptake by plants as well as chlorophyll and crude protein content in plant tissue. Among the rhizobacteria, Bacillus mucilaginosus resulted in significantly higher mobilization of potassium than Azotobacter chroococcum and Rhizobium inoculation. Overall, inoculation of maize and wheat plants with these bacteria could be used to mobilize potassium from waste mica, which in turn could be used as a source of potassium for plant growth.