Assessment of phosphorus availability in soil by introducing P-solubilizing novel bacterial and fungal strains of Lower Himalaya

Phosphorus (P) is an essential element for soil quality and plant growth. But little is known about P fractions consequent to microbial inoculation in soils amended with inorganic phosphorus. In this regard, the overall soil P fractions after microbial treatments varied as hydrochloric acid - P (HCl-P) > Sodium hydroxide - P (NaOH-P) > Sodium bicarbonate - P (NaHCO3-P) > Water - P (H2O-P) determined through sequential fractionation. Inorganic P amendment of soil increased residual P fractions indicating non-availability of chemical P fertilizers added in soil. Bacterial-fungal co-inoculation, significantly increased NaHCO3-P and H2O-P fractions, as compared to mono inoculations and un-inoculated controls. Inoculated microbial populations increased in numbers contributing to the modification of the soil pH. In soil without TriCalcium Phosphate (TCP), microbial treatments showed a reduced pH compared to the control, with a maximum pH decrease in mono bacterial inoculations. In conclusion, tested bacterial and fungal strains exhibited efficient P solubilization in soil, and thus, have potential to be used as biofertilizers, subject to other necessary trials.