Impact of Azospirillum brasilense and nitrogen dose on corn productivity

This study aimed to analyze the impact of different Azospirillum brasilense dosages, applied in the sowing furrow, combined with top-dressing nitrogen (N) fertilization, on the vegetative and reproductive development of maize. The experiment was conducted in a randomized block design, in a 4x5 bifactorial scheme, with four inoculation dosages (D0: no inoculation; D1: 167.9 mL ha⁻¹; D2: 218.3 mL ha⁻¹; and D3: 302.8 mL ha⁻¹) and five N top-dressing dosages (0, 30, 75, 120, and 195 kg ha⁻¹). Plant height, emergence speed index, total chlorophyll, thousand-grain weight, and yield were evaluated. The only parameter affected by the combination of factors was yield. Plant height and thousand-grain weight were influenced by the N dosage, which promoted the increase of these parameters. Chlorophyll content was affected by inoculation, with no difference among the applied dosages, only by the addition of the technique. It was observed that the higher the N dosage with an increase in inoculation dosage, the higher the yield. Inoculation, as an isolated N supplementation technique, resulted in the lowest yields, with the greatest yield increase found at the highest inoculation dosages.