Rhizosphere nitrogen-fixing bacteria (free-living) contribute to nitrogen absorption in wheat

A plant microbiome includes a community of microrganisms that interact extensively with the plant. The bacteria Azospirillum brasilense and Herbaspirillum seropedicae are nitrogen fixers and plant growth promoters, capable of promoting associations with the wheat crop, being a biological tool to reduce chemical fertilizers. Thus, the present work aims to evaluate the interaction of these bacteria with wheat, associated and not nitrogen fertilization. The experiment was carried out in the 2014 and 2015 agricultural seasons. The experimental design was randomized blocks in a 2 × 4 factorial scheme, with 4 replications. The first factor refers to nitrogen coverage applications (with and without nitrogen). The second factor refers to the inoculation of seeds with diazotrophic bacteria, treatment without inoculation, A. brasilense, H. seropedicae and their combination. The combined inoculation provided increments in the variables number of grains per spike, number of spikelets per spike and productivity.