Effect of Co-inoculations with Growth-Promoting Bacteria on Soybean Crop

Aim: To evaluate the effect of co-inoculation with Pseudomonas fluorescens and P. fluorescens + Azospirillum brasilense on seedling emergence speed, development and soybean yield.

Study Design: Randomized complete block design with five treatments and eight replications.

Place and Duration of Study: Ibiporã, Paraná State, Brazil, during the 2020/21 season.

Methodology: The treatments consisted of untreated control (Cont); mineral fertilizer (Min); mineral fertilizer + (P. fluorescens + A. brasiliense) (Min – Psf + Azb); mineral fertilizer + P. fluorescens at two doses (Min – Psf 100 and Min – Psf 200). The effect in the soybean was assessed by determining the effect on the seedling emergence speed, crop development and crop yield. Data were subject to ANOVA at P = 0.10 Treatments means were separated using the Duncan test at a 0.10 level of significance.

Results: The inoculant treatments had non-significant effect on the emergence speed index and crop stand. However, the co-inoculation with P. fluorescens at two doses resulted in the best plant vigor. In addition, the treatments with co-inoculation increased shoots and root biomass, with Min – Psf 100 inducing more nodules. Finally, Min – Psf + Azb and Min – Psf 200 had very significant results for soybean yield.

Conclusion: This study revealed that the co-inoculation treatments tested led to great soybean response, especially for P. fluorescens at a doubled dose, which demonstrated a significant increase in soybean development and yield in relation to the control.