EVALUATION OF THE USE OF Azospirillum brasilense AND NITROGEN FERTILIZATION IN Panicum maximum CV. MOMBAÇA

Abstract

Pasture management and beef cattle production are strategic pillars of the Brazilian economy. Brazil is a leading global beef producer, making the adoption of sustainable practices essential to reconcile high forage yields with environmental preservation. Nitrogen (N) is a critical nutrient for plant growth, enhancing biomass production and forage quality. However, intensive reliance on synthetic N fertilizers increases production costs and can lead to adverse environmental impacts. In this context, inoculation with Azospirillum brasilense, a plant growth-promoting rhizobacterium (PGPR), represents a promising alternative due to its capacity for biological nitrogen fixation and phytohormone production, which stimulate both root and shoot development. This study aimed to evaluate the fresh mass, dry mass, and plant height of Mombaça guinea grass (Megathyrus maximus cv. Mombaça) under different N fertilization rates, with and without A. brasilense inoculation. The field experiment was conducted in Diamantino, Mato Grosso State, Brazil, utilizing a randomized design with four N rates (0, 50, 100, and 150 kg ha⁻¹) in a factorial scheme with and without inoculation. The results demonstrated that the application of 150 kg ha⁻¹ of N combined with inoculation increased forage yield by 18% compared to the N-only treatment. These findings indicate that integrating synthetic N fertilization with A. brasilense inoculation is an effective strategy to enhance the agronomic performance and sustainability of Mombaça grass pastures.