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

ABSTRACT

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.

KEYWORDS:

• Phosphorus
• P fractionation
• P solubilizers
• plant nutrient
• tricalcium phosphate
• biofertilizers

Acknowledgments

The work was financially supported by research grants by Higher Education Commission (HEC) of Pakistan under IPFP/HRD/HEC/2014/964 and NRPU20-3657/R&D/HEC/14/704. Authors would also like to acknowledge Mr. Balarabe A. Inuwa for linguistic support in English redaction.

Conflict of Interest

The authors declare no conflict of interest.

Additional information

Funding

This work was supported by the Higher Education Commission (HEC) of Pakistan [IPFP/HRD/HEC/2014/964 and NRPU20-3657/R&D/HEC/14/7];