Influence of Seed Co-Inoculation with Bradyrhizobium Species and Azospirillum Brasilense on Soybean Development in Southern and Southeastern Brazil

Bioinoculants are widely used in Brazil, based on efficient and low-cost.This study aimed to evaluate the agronomic efficiency of co-inoculation with Bradyrhizobium species and Azospirillum brasilense in soybean seeds.Field trials were established in four regions of Brazil using a randomized block design with 8 treatments and 4 replications as follows: T1 -Control, T2 -200 kg ha -1 N, T3 -Bradyrhizobium spp.peat;T4 -Bradyrhizobium spp.-liquid, T5 -A.brasilense, T6 -Standard co-inoculation Bradyrhizobium spp.+ A. brasilense, T7 -Co-inoculation ratios: 1:1 Bradyrhizobium ssp.GRAP NOD L ® + A. brasilense GRAP NOD AL ® , T8 -Co-inoculation ratios: 1:1.5 Bradyrhizobium ssp.GRAP NOD L ® + A. brasilense GRAP NOD AL ® .The study results demonstrated the influence of co-inoculation 1:1.5, providing increments in shoots and root dry mass, nodules number and dry mass, pods number per plant, and yield when compared with the control and conventional N fertilization.The co-inoculation in the ratios 1:1 and 1:1.5, positively influenced the soybean development.These results confirmed that potential of the co-inoculation in incrementing soybean yield, which justify the recommendation of these treatments to reduce mineral N fertilization, improving good agronomic practices.