Brief In Vitro Analysis on Improvement of Available Phosphorous In Low Soluble Eppawala Rock Phosphate

Abstract

Rock Phosphate (RP) is any naturally occurring geological material that contains one or more phosphate minerals suitable for commercial use. There is a major RP deposit in Eppawala, Sri Lanka and this RP identify as Eppawala Rock Phosphate (ERP). Large proportion of soluble inorganic phosphate added to soil is rapidly fixed as insoluble forms soon after application. Development of an economical and environmentally friendly alternative for successful soil P management is major concern in crop production and Phosphate Solubilizing Microorganism (PSM) attracted attention in this regard. This study was conducted to identify the Phosphorus solubilizing bacteria. Soil samples were collected from different Agricultural crop lands. Soil were Spread cultured in NBRIP medium after a serial dilution. The bacterial colonies that produced clear zone of activity were considered as potential phosphate solubilizes. They were sub-cultured for the further purification. The experiment has been carried out adding 28% P2O5 containing Eppawala Rock Phosphate with NBRIP medium. Bacterial growth in 660 wave length by using shimadzu UV spectrophotometer, P solubilization, and pH were measured respectively 1, 3, 5 and 7 days after inoculation. Clear zone producing bacteria in phosphate enriched medium has been selected as P solubilizing bacteria with time period all bacterial strains has shown improvement of solubilized P in the culture media. Among them PSB-7 strain has shown a vigorous growth and maximum P Solubilization 237.61 ppm in vitro during experiment. Despite of environment unfriendly chemical solubilization methods of naturally existing Rock Phosphate this biological solubilization generate maximum amount of plant available phosphorous.