Evaluation of Phosphobacterin as a Soil Inoculant

Abstract

Abstract Characterization of Phosphobacterin obtained from the U.S.S.R. showed that it is a culture of Bacillus megaterium adsorbed on kaolinite at approximately 7 billion spores per gram. The bacteria readily decomposed glycerophosphate. Two greenhouse experiments conducted at Beltsville, Maryland, in which tomatoes and wheat were grown on six neutral soils showed a 7.5% increase in tomato yield in the first experiment, where Phosphobacterin was applied, and no increase for wheat. No such increase in tomato yields was observed in the second experiment. Neither phosphorus concentration in the two crops nor fertilizer recovery, determined with P 32 , was favorably influenced by the inoculant in either experiment. There are no indications from these experiments that Phosphobacterin inoculation of vegetable or field crops would be beneficial.