Bacterial isolates were screened for their phosphate solubilizing
ability on NBRIP and PVK media, respectively. These
media were supplemented with insoluble phosphate i.e. tri-calcium
phosphate Ca3(PO4)2 at final concentration of 0.5%. The
solubilization zone and colony diameters were measured after
120 h of incubation at 30 C. The results were expressed
according to Nguyen et al. (1992) as follows