Phosphate solubilization capacity by bacteria in soybean crops.

Area of Science:

• Agricultural Microbiology
• Plant Nutrition
• Soil Science

Background:

• Phosphorus (P) availability to plants is limited by soil P fixation to minerals and organic matter.
• Phosphate-solubilizing microorganisms (PSMs) can enhance P uptake by secreting phosphatases.
• Developing effective microbial inoculants is crucial for sustainable agriculture.

Purpose of the Study:

• To assess the phosphate solubilization capacity of coinoculated bacteria in soybean cultivation.
• To evaluate the impact of different bacterial consortia on soybean growth and P uptake.
• To identify effective bacterial strains for improving soil phosphorus availability.

Main Methods:

• Soybean plants were grown in nutrient solution with various bacterial inoculants (Bradyrhizobium japonicum, Pseudomonas fluorescens, Bacillus megaterium, Bacillus subtilis) and P doses.
• Laboratory experiments evaluated bacterial phosphate solubilization on NBRIP agar medium.
• Root dry mass and shoot P content were measured to assess treatment effects.

Main Results:

• Coinoculation with Bradyrhizobium japonicum + Bacillus subtilis increased root dry mass by 201.26%.
• Bradyrhizobium japonicum + Pseudomonas fluorescens enhanced shoot P content by 26.7% at 40 kg P ha-1.
• Bacillus subtilis demonstrated moderate phosphate solubilization in vitro, indicating potential for soil P enhancement.

Conclusions:

• Specific bacterial coinoculations significantly improve phosphorus availability and soybean plant growth.
• The combination of Bradyrhizobium japonicum with Bacillus subtilis or Pseudomonas fluorescens shows promise for enhancing soybean nutrition.
• Bacillus subtilis is a viable option for improving phosphorus use efficiency in agricultural soils.