Diferentes formas de inoculação e coinoculação de Bradyrhizobium japonicum e Azospirillum brasilense na cultura da soja

Abstract

Soy is the most produced and consumed legume in the world and the most important nutrient for its maximum vegetative and productive development and nitrogen, as it is a very expensive nutrient to be applied in the form of chemical fertilizer, besides having low effectiveness and cause pollution, the best solution found to supply this demand is with biological nitrogen fixation (FBN), and this fixation is maximized by the inoculation of symbiotic and associative bacteria in the seed of the crop. Inoculation consists of treating the crop's seeds or spraying inoculants at different vegetative stages. This work aimed to evaluate and compare the plant development and the production of the Glicyne max culture, in relation to different forms of inoculation and coinoculation of the bacteria Bradyrhizobium japonicum and Azospirillum brasilense. These bacteria have the main function of making biological nitrogen fixation (BNF) in the soil for the use of plants. The methodology of the work was to compare the current form of inoculation of these bacteria, which is done in the pre-planting seed, with the inoculation of the bacteria by spraying on other vegetative stages of the plant (V2 and V6). Coinoculation was also performed, that is, inoculating the two bacteria at once. The work was developed with 12 treatments and 3 repetitions, totaling 36 plots, being considered Witness the treatment already used by the farmers, and was done in a randomized block design, implanted 5m x 2.5m plots and having a useful area for evaluation of 3m x 1.5m. Inoculants were used in liquid form with a concentration of 1.1x109 CFU/ml for both Bradyrhizobium japonicum and Azospirillum brasilense, for sowing 5 rows with 50 cm spacing between rows and 10 cm between plants. The variables analyzed were chlorophyll level (g), plant height (cm), shoot dry mass (g), number of pods per plant, productivity (kg ha-1) and weight of a thousand grains (g). The data obtained were subjected to analysis of variance and Tukey's test at 5% probability, showing that the tested treatments did not significantly influence the variables considered, thus concluding that in relation to the form of inoculation and co-inoculation of bacteria Bradyrhizobium japonicum and Azospirillum brasilense, there is no direct interference in the variables analyzed, in an area already cultivated with soy.