Doses complementares de inoculante (Bradyrhizobium japonicum) via foliar em diferentes estádios vegetativos na cultura de soja

Abstract

The objective of this study was to evaluate the effect of different doses of complementary liquid inoculant applied in the vegetative stages V2, V4 and V6 on the following variables: number of nodules, dry mass of nodules, root dry mass, mass dry grain and productivity. The experimental design was in randomized blocks (DBC) with four replications in a factorial scheme 5x3 totaling 60 plots. The first factor was the application of the liquid inoculant with the bacterium Bradyrhizobium japonicum at doses: 0; 75; 150; 225 and 300mL ha -1 at the concentration of 7.5x109 CFU per mL. And the second factor was the times of application in the vegetative stages: V2, V4 and V6. Data were submitted to analysis of variance at 5% probability level for F test, and Tukey test for comparison of means for significant results. The applications of 75 mL ha-1in the V4 stage, 150 mL ha-1 in V2 and V6 and 300 mL ha-1 in V4 and V6, reached the highest numbers of nodules, and the highest average treatment was the application of 300 mL ha-1 in the V6 stage. For dry mass of nodules the application of 150 mL ha-1 in V6, presenting the best average in the value 1.4 g. There were no significant differences in treatments on the following variables: root dry mass, dry mass of one thousand grains and productivity. The use of foliar inoculant is recommended when there is failure or no other type of inoculation is done.