Microbial Efficacy of Phosphate Solubilization in Agro-Saline Soils of Various Areas of Sindh Region

ABSTRACT AIMS AND OBJECTIVES The essence of this work is: To isolate the microorganisms having greater phosphate solubilization activity. (ii) To observe the specific time duration (days/ hours) for the phosphate solubilization process by the test isolates. Materials and Method Eighty five soil samples were collected from 20cm depth from the cultivated lands (near salinity areas) of wheat, sugar cane, banana and rice. One DETERMINATION OF PHOSPHATE SOLUBILIZING ACTIVITY Liquid Phase Method The grown cultures of microbial isolates were subcultured separately in PVK broth medium for 24, 48, 72 hours and 1 week for the growth of bacterial and fungal isolates. After a week fungal mycelia were removed and the solution was used for further process. Ten (10) ml of the each culture were centrifuged at 12000 rpm for 15 minutes, 5 ml of the supernatants were poured into 20 ml of AB-DTPA Disc Diffusion Method Discs of 6mm were prepared from Whattman filter paper and sterilized in autoclave at 121ºC, 15 lbs, 20 minutes, later dried in oven at 50ºC for 30 minutes. Using sterile forceps the discs were dipped separately into the broth culture and kept in the center of the surface of PVK agar. The plates were incubated at 37ºC for 24-72 h and at room temperature for 1 week for the appearance of halo zone of Psa by test bacterial and fungal isolates. Determination of Percentage of Psa by Microbial Isolates [26] RESULTS AND DISCUSSION Eighty five saline soil samples were collected from various areas of cultivated lands of different cities of Sindh Province. and Arthrobacter sp (9.41%), which are the important for Psa. From the observations it was also revealed that fungi especially Aspergillus sp. showed increasing Psa and reached at maximum peak after 9 days and showed halo zone after 9 days of incubation as compared to the other fungi. On the other hand Bacillus sp. showed maximum peak and halo zone after 48 hours as compared to the other bacteria. The observations has the highest halo zone of 3.6mm giving 60% Psa after 9 days and Bacillus sp. indicated that it has 1.6mm halo zones showing 53.33% Psa after 48 hour due to the greater enzymatic activity. This observations revealed that the soil samples In-vitro acid production in the test PVK broth is the increased phosphorous production (μg/ ml) with in 8-9 days decreasing the pH of the medium from 7.2-6.5 and 7. CONCLUSION From the above observations, it is concluded that f u n g a l i s o l a t e s h a v e t h e g r e a t e r a c t i v i t y o f phosphate solubilization (60%) than bacteria (53.33%). It is also concluded that Aspergillus sp. and Bacillus sp. that showed halo zone after 7 days and 72 hour time respectively as compared to other species of their respected groups. It is also concluded that Aspergellus sp. and Bacillus sp. ar