Avaliação de cepas microbianas associadas à adubação nitrogenada na cultura do milho em diferentes condições edafoclimáticas

Abstract

Maize (Zea mays L.) is one of the most economically important crops in Brazil and has a high nitrogen (N) demand to achieve elevated yields. However, the intensive use of mineral fertilizers has increased production costs and caused significant environmental impacts. In this context, the use of plant growth promoting and nitrogen-fixing bacteria, such as Herbaspirillum seropedicae, emerges as a sustainable alternative to improve N use efficiency and reduce dependence on synthetic fertilizers. This study evaluated the effect of inoculating different strains of H. seropedicae, alone or in combination, associated with nitrogen fertilization, on maize development and yield under the edaphoclimatic conditions of Guarapuava and Londrina, Paraná, during the 2024/2025 growing season. The experiment was conducted in a randomized block design with eight treatments, including controls, commercial products, and experimental inoculants. Morphological and agronomic traits were evaluated and subjected to ANOVA and the Scott–Knott test at 5% probability. Plant height and first ear insertion showed significant differences among treatments in Londrina, while no expressive changes were observed in Guarapuava. Regarding yield, responses varied between sites: in Guarapuava, the treatment Bac 3, containing two strains of H. seropedicae, showed the highest yield, surpassing the controls and commercial products. In Londrina, the Bac 2 treatment (Azospirillum sp. + Herbaspirillum sp.) stood out, with performance similar to commercial standards. These results demonstrate that the response to inoculation depends on environmental conditions and nitrogen management but reinforce the potential of Herbaspirillum seropedicae as a plant growth promoter and complementary contributor to biological nitrogen fixation in maize. Therefore, the evaluated inoculants represent a promising alternative to make production systems more efficient and sustainable.