Efficiency of Bacillus coagulans as P biofertilizer to mobilize native soil organic and poorly soluble phosphates and increase crop yield

Abstract

Bacillus coagulans, a phosphatase- and phytase-producing bacterium was isolated and tested under greenhouse conditions and in the field in a loamy sand soil. Bacterial population build-up and efficiency was compared under sterilized and non-sterilized soil conditions. Exploitation of plant unavailable (poorly soluble) P was higher in sterilized soil, mainly due to an increased bacteria population. A gradual increase in microbial build-up of up to 21 times the inoculated population was observed over a 4-week period under the sterilized soil condition. Clusterbean influenced acid phosphatase and phytase activity. The depletion of organic P was much higher than the depletion of mineral and phytin P. The microbial contribution to the hydrolysis of the different P fractions was significantly higher than the plant contribution. The maximum effect of inoculation on different enzyme activities (acid phosphatase, alkaline phosphatase, phytase and dehydrogenase) was observed in pants between 5 and 8 weeks of age. A significant improvement in plant biomass (25%), root length (28%), plant P concentration (22%), seed (19%) and straw yield (28%) resulted from inoculation. The results suggested that B. coagulans produces phosphatases and phytase, which mobilized P from unavailable native P sources and enhanced the production of clusterbean.