Interferência dos capins massai (Panicum maximum x Panicum infestum cv. massai), braquiarão (Urochloa brizantha cv. marandu) e andropongon (Andropogon gayanus) sobre capim capeta (Sporobolus indicus) e capim navalha (Paspalum virgatum)

Abstract

Hindering the production of animal feed. Given the difficulty of chemically controlling these species, the potential of forage grasses massai grass (Panicum maximum × Panicum infestum cv. Massai), palisade grass (Urochloa brizantha cv. Marandu), and gamba grass (Andropogon gayanus) was evaluated as alternatives to suppress the growth of these weeds. In the first experiment, weed seeds were treated with aqueous extracts of the forage species at concentrations of 0%, 5%, 10%, and 20%. The results showed that the extracts, especially at higher concentrations, significantly reduced weed germination, indicating a possible allelopathic effect. In the second experiment, the competitive ability of the forage grasses against the weeds was tested at different densities (0, 2, 4, 6, 8, 10, and 12 plants m−2). Each forage grass was grown in competition with smut grass and virgata grass until the flowering stage of the weeds. At the end of the period, the shoot dry biomass was measured to assess interference. It was observed that gamba grass was the most effective in suppressing both virgata grass and smut grass. Higher weed densities (8, 10, and 12 plants m−2) had a greater impact on forage growth, but even so, the forages demonstrated competitive ability. It was concluded that the studied forage grasses can be used as a strategy for integrated management, reducing the infestation of smut grass and virgata grass without relying exclusively on herbicides. Gamba grass stood out as the best option for areas predominantly infested with these weeds. These results suggest that the use of these forage grasses in grazing systems or intercropping may contribute to the sustainable control of weeds in pastures.