Inoculation, co-inoculation and nitrogen fertilization in soybean culture

Abstract

The objective was to evaluate the inoculation, co-inoculation with bacteria B. japonicum and A. brasilense in combination with application of N doses on the agronomic characteristics of soybean. The design used was randomized blocks in a 4x4 factorial scheme, with four types of inoculation (absence of inoculation, inoculation of B. japonicum bacteria, inoculation with A. brasilense and co-inoculation with B. japonicum and A. brasilense) and four doses of N (0 % = 0; 2 % = 4.5; 4 % = 9 and 8 % = 18 kg ha-1), with four replications. The increasing doses and above 2% of N promoted a reduction in the number of nodules formed by B. japonicum in the roots. The number of nodules and root dry mass was higher at the dose of 8% N, with an average of 317 nodules per plant and 23.42 g plant-1 referring to the treatment with the inoculant A. brasilense. The nodulation efficiency obtained a value of 354 g kg-1 when the dose of 2% of N was used. if co-inoculation. The practice of nitrogen fertilization resulted in an increase in the number of nodules only for the bacteria A. brasilense and significant gains of N in the plant only at the dose of 8% of N.