RESUMEN
Abstract The objective of this research was to identify the best microorganisms, alone or in mixture for total biomass gain (root + shoot), positive change in gas exchange, nutrient uptake (root, shoot and grain) and yield and yield components in the soybean crop. Trial under greenhouse conditions had the experimental design in a completely randomized scheme with 26 treatments and four replicates. The treatments consisted of the rhizobacteria BRM 32109, BRM 32110 and 1301 (Bacillus sp.), BRM 32111 and BRM 32112 (Pseudomonas sp.), BRM 32113 (Burkholderia sp.), BRM 32114 (Serratia sp.), Ab-V5 (Azospirillum brasilense) and 1381 (Azospirillum sp.), and the fungus Trichoderma asperellum (a mix of the isolates UFRA.T06, UFRA.T09, UFRA.T12 and UFRA.T52). Besides, the same isolates were combined in pairs, completing 16 combinations. Control treatments received no microorganism. Microorganisms applied isolated or in combination, provided biomass gain, positive gas exchange, increases in nutrients uptake at the shoot and grain, and improved grain yield and its components than control plants. Stood out the combination Ab-V5 + T. asperellum pool, which provided a 25% improvement in grain yield.