Co-Inoculation by Spraying on Soybean (Glycine max L.) Under Vegetative Phase

Abstract

The use of inoculants revolutionized the soybean production system, increasing grain production, reducing the use of chemical fertilizers, and costs. The inoculation with Bradyrhizobium japonicum and the co-inoculation with more than one type of microorganisms are recommended directly in the seed or in the planting furrow, with high efficiency, bringing beneficial results related to the increase in the number of nodules and improvements in the physiology of the soybean plants. In order to increase productivity bringing new methods of using these microorganisms, this study aimed to evaluate the development of soybean culture under co-inoculation by spraying with Azospirilum brasilense and B. japonicum was carried out, in the vegetative stage. One field experiment was conducted from September to January, harvest of 2018/2019, in the commercial area under no-tillage. The evaluated treatments were: Control (C) without microorganisms; T1 (6x10⁸ mL^-1 of A. brasilense and 0 of B. japonicum); T2 (6x10⁸ mL^-1 of A. brasilense and 6x10⁹ mL^-1 of B. japonicum); T3 (12x10⁸ mL^-1 of A. brasilense and 0 of B. japonicum); and T4 (12x10⁸ mL^-1 of A. brasilense and 12x10⁹ mL^-1 of B. japonicum). The results showed that there was an increase in the number and matter of nodules, plant height, number of pods and grains in the T4 treatment, showing a significant difference mainly in relation to the control. It was concluded that co-inoculation with B. japonicum and A. brasilense by spraying in the vegetative stage proved to be efficient, demonstrating the potential use of this technique.