Actinomycete isolates and arbuscular mycorrhizal fungi were evaluated in vivo using jointly inoculation systems with soybean plants inoculated with rhizobia, with the aim to observe microbial interactions. The study was carried out at the National Center of Agrobiologic Research (Embrapa CNPAB). Soil of the Itaguai series (medium texture) was used as substrate mixed with river sand in proportion 1:1 (v:v), adding actinomycete isolates (ACT 78 and ACT 370), rhizobia strains (Bradyrhizobium elkanii - BR 29 and Bradyrhizobium japonicum - BR 33), and arbuscular mycorrhizal fungi (Gigaspora margarita and Glomus clarum). The results revealed the effect of the arbuscular mycorrhizal fungi addition with significant and expressive influence on growth parameters, nodulation and density of actinomycete isolates on the soybean rhizosphere which showed greater values compared with fungi uninoculated plants. Synergistic and antagonistic effects were observed between the arbuscular mycorrhizal fungi with actinomycetes isolates and rhizobia strains.
biological nitrogen fixation; microbial interactions; synergism; antagonism
