Influence of pre-inoculation of soybean seeds with Bradyrhizobium 15 days before sowing

Abstract

Nitrogen is an essential nutrient for the soybean cultivation, which can be fully supplied by the biological nitrogen fixation process. This study evaluated the effectiveness of pre-inoculation of soybean seeds with the inoculant Biofix Protec (Bradyrhizobium diazoefficiens SEMIA 5080 and Bradyrhizobium japonicum SEMIA 5079, 5x109 UFC/mL), accompanied by cell protector and chemical treatment. Four trials were done in Brazilian states during the soybean harvest 2021/2022, following a randomized complete block design with six replications. The cultivars used were TMG 7067 IPRO Inox, BRS 245 RR, N 7780 PRO, and Extrema IPRO, chosen according to the characteristics of each region. The treatments were: T1- Control, without inoculation; T2- Fertilization with 200 kg/ha of nitrogen; T3- Inoculation with commercial inoculant (50 mL/50 kg of seeds) on the day of sowing; T4- Biofix Protec (100 mL/50 kg of seeds), cell protector (0.5 mL/kg), Potenzial TS (0.2 mL/kg) and CoMo Platinum (100 mL/ha), all applied 15 days before planting. The results indicated that the application of Biofix Protec 15 days before planting increased the nodulation of the main root and the dry mass of nodules. The pre-inoculation of Biofix Protect, with protective agents and chemical treatments, demonstrated comparable efficacy to the inoculation carried out at the time of sowing and increase in yield between 4.8-11%, compared to the control, being statistically equivalent or superior to the commercial inoculant available in the market, applied on the day of sowing. The use of Biofix Protec favored nodulation and enhanced productivity, being recommended for the treatment of soybean seeds in agricultural production systems.