Abstract
A laboratory experiment was conducted to study the effect of bacterial inoculation rock phosphate solubilization in the presence or absence of rock phosphate under different levels of organic matter (0, 10, 20 gm.kg-1) and in sterile and non sterile soil. The results indicated the following; Phosphate potential values were increased after 1% rock phosphate addition as compared with the control treatment (0% rock phosphate) in about 91% , also phosphate potential values were increased in soil amended with both levels of the organic matter as compared with the control treatment (0 gm.kg-1 organic manure). Increasing the organic matter level from 10 to 20 increased the phosphate potential (30 – 155%) , the values of phosphate potential were greater in the non–sterilized soil than the sterilized soil in about 9% . Results showed also that Bacillus subtilis increased phosphate potential 104.5% while Pseudomonas fluorescence bacteria was increased the phosphate potential about 74.5% . Results of P solubility by using solubility diagram showed that most of the points were under saturated with DCPD at 7 days period and no indication of hydroxyl apatite formation in this experiment after 56 days.
