Multivariate Approach in the Initial Development of Soybean as a Function of Co-inoculation and Micronutrients

Co-inoculation in soybean is the mixed inoculation with bacterias of the genus Bradyrhizobium and Azospirillum brasilense. The applicability of this practice has become the subject of recent research that aims to overcome the main limitations of biological nitrogen fixation, obtained by traditional soybean inoculation with only Bradyrhizobium. This study investigated the interaction effects among cultivars, bacterium types, with and without micronutrients applied to the seeds on the initial developmental stages of soybean cultivars using multivariate analyses. The seedlings were cultivated in pots filled with soil in greenhouse conditions. The experiment was installed in the Alta Mogiana branch of the Paulista Agribusiness Technology Agency (APTA) in Colina, SP. The 32 treatments were arranged as 4 × 4 × 2 factorial with four soybean cultivars, four bacterium types, with and without micronutrients applied to the seeds. The evaluations were performed at 5, 8 and 32 days after sowing (DAS). The parameters analyzed in the pots showed that the cultivars behaved differently depending on the type of bacteria used. The co-inoculation promoted better nodulation and initial seedling growth in some cultivars. In general, cultivars without application of micronutrients were superior in terms of the parameters analyzed.