Effect of inoculant with technologies integrated in initial soybean growth

Abstract

Soybeans are one of the most produced grains in the world, and because of the high cost of nitrogen fertilizers, new technologies in the inoculation of diazotrophic bacteria have been developed. The objective of this study was to evaluate the effect of Bradyrhizobium-based inoculant doses and Lipo-chito-oligosaccharide molecules (LCOs), together with bacterial protector as an additive, compared to a conventional inoculant in the inoculation of soybean seeds. The experiment was carried out in a greenhouse, with soil from a Red Oxissol of sandy texture. The experimental design was in randomized blocks with 3 replicates, the treatments being distributed in a 5 x 2 factorial scheme (2 inoculants and 5 inoculant doses). The seeds of the soybean cultivar M8866 were inoculated and seeded in the pots containing 11 L of substrate, where two plants remained for 45 days. Nine biometric-productive parameters were evaluated. Increasing the dose, regardless of the inoculant, provided an increase in root length and probably active nodules. In general, it was possible to observe statistical superiority of the inoculant with technologies integrated in relation to the conventional one, independent of the dose, when comparing the inoculants with respect to these two variables. Furthermore, the inoculant with integrated technologies provided a higher mass of fresh and dry matter of the nodules with the application of the highest inoculant dose (3.6 billion UFC mL-1). It was noted that increasing the dose of conventional inoculant did not cause the increase of fresh and dry matter mass of the nodules such as the inoculant with integrated technologies, suggesting the beneficial action of the bioprotectant and of the LCOs molecules.