Evaluation of Agronomic Efficiency and Practicality of Biomax® Azum Foliar Inoculation (Azospirillum brasilense – 3 × 10⁸ CFU mL− 1) as a Plant Growth Promoter in Maize (Zea mays)

Abstract

Although plant growth-promoting bacteria (PGPB) like Azospirillum brasilense enhance maize production, traditional seed or furrow inoculations face operational constraints, and the agronomic field efficiency of foliar alternatives remains inconsistent. This study aimed to evaluate the agronomic efficiency and practicality of foliar application of the commercial inoculant Biomax® Azum (Azospirillum brasilense – 3 × 10⁸ CFU mL-1) as a plant growth promoter in maize (Zea mays). Field experiments were conducted during two cropping seasons in three different Brazilian regions (Santa Maria–RS, Querência–MT, and Uberlândia–MG). Treatments included seed, in-furrow, and foliar inoculations (200 and 300 mL ha⁻¹), as well as a non-inoculated control. Variables evaluated included shoot dry matter, nitrogen content in shoots and grains, yield components, and final grain yield. Results showed that foliar inoculation, particularly at 200 mL ha⁻¹, significantly increased biomass and grain yield under specific conditions, being comparable or superior to other application methods. It was concluded that foliar inoculation with Biomax® Azum is an agronomically effective and feasible strategy for maize cultivation, especially under favorable edaphoclimatic conditions.