Technical and Economic Viability of Corn with Azospirillum brasilense Associated with Acidity Correctives and Nitrogen

There is a lack of more comprehensive research defining how much mineral N can be applied as regards the efficiency of BNF to attain high with Azospirillum brasilense, what is a bacterium that stands out for its biological nitrogen fixation (BNF) in corn crops, reaching economically sustainable yields. Moreover, it would be interesting to investigate the use of silicon, which exerts numerous benefits on grasses, especially when the plants are subjected to biotic and abiotic stresses. The aim of this work was to study a synergistic effect between the inoculation with A. brasilense and the application of silicon, thus enabling a higher efficiency of nitrogen fertilization, evaluating the grain yield of irrigated corn in economic terms. The experiment was conducted in Selvíria, MS, Brazil, under a no-till system, on a Latossolo Vermelho distrófico (Oxisol). The experiment was set up as a randomized block design with four replications, in a 2 × 5 × 2 factorial arrangement consisting of two soil corrective sources (dolomitic limestone and Ca and Mg silicate as source of Si); five doses of N (0, 50, 100, 150 and 200 kg ha-1); with and without inoculation with A. brasilense. The inoculation makes the corn increase much more profitable, irrespective of N doses and corrective source. The N dose of 200 kg ha-1 with dolomitic limestone, associated with inoculation provided greater grain yield. However, the highest economic return was obtained at the N dose of 100 kg ha-1, with dolomitic limestone application and inoculation.