Resposta dos capins Andropogon (Andropogon gayanus) e Marandu (Urochloa brizantha cv. Marandu) à adubação foliar: vigor, crescimento e morfologia

Abstract

The objective of this study was to evaluate the initial growth and regrowth vigor of Andropogon grass (Andropogon gayanus) and Marandu grass (Urochloa brizantha cv. Marandu) subjected to different doses of foliar nitrogen fertilization, analyzing the morphophysiological performance and adaptive responses of these species under controlled conditions. The experiment was conducted in a greenhouse covered with 50% shade net, using pots as experimental units in a completely randomized design, with treatments corresponding to the nitrogen doses applied via foliar spraying. The evaluated variables included plant height, number of tillers, number of live leaves, leaf length and width, as well as regrowth vigor after cutting.

The results showed that Andropogon grass responded positively to moderate nitrogen fertilization, with increased initial growth, while higher doses did not promote significant gains, possibly due to physiological limitations in nitrogen utilization. In contrast, Marandu grass exhibited more stable behavior across the tested doses, reflecting greater efficiency in nutrient use and morphophysiological balance. Overall, foliar nitrogen fertilization directly influenced the vegetative development of the grasses, highlighting adaptive differences between the species.

It is concluded that Andropogon stands out for its rusticity and adaptability to low-fertility environments, whereas Marandu presents higher productive potential when subjected to adequate nutritional management. Therefore, species selection and proper fertilization management are decisive factors for ensuring efficiency and sustainability of forage production in semi-arid regions.