Eficiência do Azospirillum brasiliense associado à adubação nitrogenada sobre as características agronômicas do milheto e valor nutricional de sua silagem

Abstract

Millet is an annual crop adapted to the production of silage in the semiarid region. Its production can be increased with the use of nitrogen. However, due to their high value, growth-promoting bacteria such as Azospirillum brasilense have been tested as an alternative. Thus, the objective was to determine the best dose of Azospirillum brasilense that provides greater productivity and nutritional value of the entire plant and millet silage, associated or not with nitrogen fertilization. A randomized block design in a 4 x 2 factorial arrangement was used, with four doses of Azospirillum brasilense solution (0, 10, 20, 30-liter ha-1 ), associated or not with conventional urea, with five replications. There was no interaction between the factors, Azospirillum brasilense and nitrogen for the studied variables. The spraying of 30 liters increased 6.80% in the height of the plant, and 23.88% in the production of dry matter per ha when compared to treatments that do not received the spray of the bacteria. The 30-liter dose reduced 2.18% in the crude protein content by and 2.73% in the total digestible nutrients. However, the dose of 30 liters produced 562.33 kg of crude protein and 2,898.16 per ha-1 of total digestible nutrients more than the treatments that did not receive the spray. The dose of 30 liters produces a greater amount of dry matter per ha-1 , and reduces the nutritional value, however it results in greater production of crude protein and total digestible nutrients per hectare. Azospirillum brasilense proves to be a sustainable technology with good productivity, and the application of nitrogen fertilization did not increase the production of dry matter per hectare.