Different methods of inoculation of nitrogen-fixing bacteria (Azospirillum) specific of grasses in sorghum

Abstract

Sorghum is one of the crops of great relevance in the production of grains in the cerrado region. Its main use for animal feeding and is considered a great alternative for human food in the form of grains. A promising alternative is the use of nitrogen-fixing bacteria (N) in the sorghum crop. Inoculation with N-fixing bacteria, such as Azospirillum, is an alternative to reduce costs by replacing the high cost of production due to nitrogen fertilization. The objective of this work was to evaluate different methods of inoculating nitrogen - fixing bacteria (Azospirilum) in sorghum culture. The experiment was carried out in the city of Goianésia, Goiás, Brazil. The experimental design was randomized blocks with five treatments, using 4 replicates per treatment, arranged in different methods of inoculation of Azospirillun brasilense in sorghum: control inoculation, seed treatment, application in furrow, application in cover after sowing and application 10 days after emergence. To determine growth and development, the following evaluations were made: stem thickness, root length, root volume, number of nodes, fresh shoot mass and shoot dry mass. Seed inoculation presented superiority in relation to other treatments regarding root length, number of nodes, green mass and dry mass. The inoculation with Azospirillum promoted positive effects on shoot thickness and root length, obtaining significant amounts and seed inoculation with the best results.