Produção de forragem, composição química e morfogênese de Brachiaria humidicola cv. Tupi em diferentes idades de corte

Abstract

The effects of plant age (14, 21, 28, 35 and 42 days) on dry matter (DM) yield, chemical composition and morphogenetic and structural characteristics of Brachiaria humidicola cv. Tupi, was evaluated under greenhouse with natural conditions of light and temperature. DM yields and regrowth, leaf blade lenght, and lifespan rate increased consistently with growth stage, however the nitrogen, phosphorus, magnesium, and potassium contents decreased as plant age, while calcium contents were not affected by plant age. For all plant ages, nitrogen contents were lower than its critic level. Maximum leaf appearance and elongation rates, and blade lenght were obtained with cutting at 41.1; 31.3 and 38.9 days, respectively. These data suggest that cutting at 28 to 42 days were optimal for obtain maximum yields and regrowth of rich forage and pasture persistence.