Doses de potássio na produção e qualidade de gramíneas forrageiras

Abstract

The aim of this study was to evaluate the effect of doses of potassium in dry matter (DM) production, neutral detergent fiber (NDF) levels, crude protein (CP) and nutrients concentration (P, K, Ca, Mg, S, Cu, Mn, Fe and Zn) in two cultivars of forage grass of genre Panicum and two of genre Cynodon. The experiments were conducted in randomized block design with four replications in a factorial arrangement with two factors being studied, with constant doses of potassium for the two experiments, equivalent to 0, 40, 80, 120, 160 kg ha-1 of K2O and cultivars of forage grass divided into two experimental groups, the first one being composed of mombaça and tanzânia (genre Panicum) and the second one by florakirk and florona (genre Cynodon). Two cuts were made to collect forage during the experimental phase of the study. The forage samplings were analyzed through the data of dry matter production, NDF levels, crude protein level and nutrients concentration. The results show that the potassium fertilization performed under the specific conditions of this study does not generate significant answers in DM production. In the rates used, the inclusion of higher levels of K did not affect the quality (NDF and CP) of the forage. The growing doses of potassium boosted a linear increase in the concentration of K in the florakirk, florona and tanzânia forage. Furthermore, they boosted an increase in the concentration of Mn in florakirk and florona. As for tanzânia, this increase occurred up to the dose of 120 kg of K2O ha-1. The growing doses of potassium were also responsible for the decrease in the concentration of Ca in Panicum cultivars.