Impact of phosphate solubilizing bacteria in combination with di-ammonium phosphate on growth and development of sunflower (Helianthus annus L.)

Abstract

Phosphate solubilizing bacteria (PSB) is renowned for its excellent potential of converting unavailable forms of phosphorus (P) to a simpler available form in the soil. This P availability not only improves plant growth and differentiation but also plays a pivotal role in balancing the soil mineral content. This study focuses on the effect of PSB alone or in combination with di-ammonium phosphate (DAP) on the growth and development of sunflower. The hybrid sunflower seeds inoculated with PSB were placed in the pots containing sterile soil. Five PSB strains, three doses of DAP, and un-inoculated seeds as the control for each dose of DAP were used. Various parameters of plant growth and soil properties were measured after 60 days of sowing. The results indicated that PSB inoculations enhanced the P mobilization efficiently in the sunflower plant and increased its growth. It also improved the availability of P in soil with a decline in soil pH. However, when PSB was used with a combination of DAP, much vaster results were noticed. Improvements in all plant growth parameters without the inoculation were higher at 30 mg kg⁻¹ DAP, which is about at 23 mg kg⁻¹ DAP when it is used in combination with PSB. Maximum SPADE chlorophyll contents, plant height, root length, fresh weight, dry weight, shoot P content, and available P in soil were assessed in AM-4 (Pseudomonas sp.) at all doses of DAP. However, the plants that were treated with 30 mg kg⁻¹ DAP showed superior results in terms of growth. The results from the study conclude that PSB can be used alone or in combination with DAP to enhance the growth of sunflower and to solubilize the fixed soil P.

Keywords:

• di-ammonium phosphate
• phosphate solubilizing bacteria
• soil available phosphorus
• sunflower

Acknowledgments

We acknowledge the University of Arid Agriculture (UAAR), Rawalpindi, Pakistan, and National Agriculture Research Center (NARC), Islamabad, Pakistan for providing Phosphate Solubilizes Bacterial (PSB) strains and other inputs required to experiment.

Conflicts of interest

The authors have no conflict of interest. All authors contributed to conduct the experiment and write up of the article. This paper is extracted from the thesis of Ph.D. studies.

Additional information

Funding

There is no funding for this research project.