Agronomic efficiency of pre-inoculating soybean seeds with <i>Bradyrhizobium elkanii</i> and a cell protector

Abstract

The objective of this study was to evaluate the efficiency and agronomic practicality of pre-inoculating soybean seeds with Bradyrhizobium elkanii (Lalfix Nitro) and a cell protector (Add-it) under field conditions. The trials were conducted in different Brazilian soil and climate regions (Brotas-SP, Caibaté-RS, Lavras-MG and Unaí-MG). The experimental design was randomized blocks, with six treatments and 10 replications. The treatments consisted of different inoculation times of the liquid inoculant Lalfix Nitro (4 mL kg^-1 of seeds) + cell bioprotector Add-it (2 mL kg^-1 of seeds): on the day of planting (LNT0), 25 days (LNT25) and 30 days (LNT30) before planting. In addition, a standard control was used consisting of a peat inoculant (Brasiliec TS IN BOX®; 60 g per 50 kg of seeds) (PI); an N-mineral control, with the recommended nitrogen fertilizer for the crop (NI+N); and a treatment with no fertilizer added and no inoculation (Control). In general, the pre-inoculation of LN + Add bioprotector up to 30 days before planting promoted a significant increase in nodulation. In addition, pre-inoculation ensured yield equal to or greater than peat inoculant and mineral N application.