Nitrogênio associado a Azospirillum brasilense na produção de milho cultivado em consórcio com cana-de-açúcar

Abstract

The high cost of nitrogen fertilizers has driven the search for more sustainable alternatives, such as inoculation with plant growth-promoting bacteria, notably Azospirillum brasilense, aiming to increase the efficiency and profitability of production systems. The hypothesis is that inoculation with Azospirillum brasilense increases nitrogen use efficiency in maize grown in intercropping with sugarcane, resulting in improvements in growth, development, and yield parameters of the crop. Thus, this study aimed to evaluate the influence of inoculation with Azospirillum brasilense, associated with nitrogen rates, on the agronomic parameters of maize cultivated in intercropping with sugarcane over two cycles. The experiment was conducted in a randomized complete block design, in a factorial scheme, with four replications. The sources of variation corresponded to inoculations with Azospirillum brasilense [NI: no inoculation; SD: standard dose; 3SD: triple standard dose] and urea rates [D0 = 0; D60 = 60; D120 = 120; and D240 = 240 kg ha⁻¹ of N]. The following variables were evaluated: plant height, ear insertion height, stalk diameter, ear diameter, ear length, number of kernel rows, number of kernels per row, total kernels per ear, and grain yield. The rate of 240 kg ha⁻¹ of nitrogen was associated with plant height, ear insertion height, ear diameter, ear length, number of kernels per row, total kernels per ear, and grain yield. Inoculation with Azospirillum brasilense at double dose influenced morphological attributes such as plant height, ear insertion height, number of kernel rows, and total kernels per ear, while at triple dose it influenced ear insertion height, stalk diameter, and total kernels per ear. Keywords: plant growth-promoting bacteria; yield; Zea mays; morphological parameters.