Agronomic characteristics of soybean as a function of inoculation, co-inoculation and N doses on eutrophic red latosol

Abstract

The objective was to evaluate the agronomic traits of soybean as a function of inoculation, co-inoculation and N doses in Eutroferric RED OXSOL. The design was randomized blocks in a 4x4 factorial scheme, with four types of inoculation and four doses of N (0 = 0; 2 = 4.5; 4 = 9 and 8 % = 18 kg ha-1). No significant differences were found for plant height, number of pods per plant, number of grains per pod, nitrogen accumulation in the plant and grain yield. The mean number of nodules was higher at the dose of 2% N, equivalent to 46 nodules per plant inoculated with B. japonicum, and in the variables of dry mass of nodules, roots and shoots, inoculated with A. brasilense at the dose of 8% had higher averages with 486.94 mg plant-1, 11.91 g plant-1, 95.5 g plant-1, respectively. Nodulation efficiency had a linear increase for a dose of 8% N with a value of 72.32 g kg-1. For the number of nodules and nodulation efficiency, there was a significant increase when using the dose of 2% of N. Using the doses of 8%, the dry mass of nodules, root, aerial part and nodulation efficiency, obtained more satisfactory results than the other doses.