Forage yield, chemical composition and macronutrient extraction of Trachypogon plumosus pastures intercropping with Stylosanthes capitata cv. Lavradeiro under potassium levels

Abstract

Was evaluated the effect of potassium fertilization (0, 40, 80 and 120 kg of K2O ha-1) on the forage yield, chemical composition and macronutrients extraction of Trachypogon plumosus native pastures intercropping with Stylosanthes capitata cv. Lavradeiro in Roraima´s savannas. The effects of potassium fertilization on legume forage yield were directly proportional to K levels, while for grass the adjustment was quadratic and the maximum value estimated with the application of 69.9 kg of K2O ha-1. Nitrogen, calcium, magnesium and potassium contents of the grass and legume were quadratically affected by potassium fertilization, while the macronutrient extraction by the grass was quadratic, and linear and positive for forage legume. Macronutrient extractions by grass and legume, independently of potassium fertilization, were higher for N and K, followed by Ca, Mg and P. Potassium fertilization provided grass and legume forage with better quality and lower fiber contents. Considering the overall availability of forage and pasture botanical composition - satisfactory grass/legume relationship - the use of potassium levels between 80 and 100 kg of K2O ha-1 allow the establishment and yield stability and persistence of grass-legume mixture.