HERBAGE YIELD AND STRUCTURAL CHARACTERISTICS OF FIVE Brachiaria GENUS FORAGES UNDER INTERMITTENTLY DEFOLIATION SWARD

Abstract

This experiment happened from July 2004 to September 2005 in the Depressão Cuiabana region-MT. The objective of this study was to verify the yield and sward structure of five Brachiaria genus forages submitted to 10 and 20 cm cutting intensities. The forages were irrigated and fertilized. The cutting happened with the frequency of 30 days. The variables analyzed were forage yield, plant height, forage bulk density, leaf blade percentage, stem percentage, leaf blade/stem relation and senescence percentage. A complete randomized block design was used with treatments in a split-plot arrangement and three replications. The Mulato grass showed highest green dry matter yield (4,2 t DM/ha) followed by Xaraés palisadegrass, Signalgrass and Ruzi grass, with averages greater than 3,5 t DM/ha, while the smallest forage yield was the Marandu palisadegrass (2,9 t DM/ha). The defoliation intensity interfered in the forage structures characteristics, but cutting intensity at 20 cm favored the highest leaf blade percentage for Xaraés palisadegrass. The smallest defoliation intensity propitiated greater forage yield with higher leaf blade percentage and smaller senescence losses during the experimental period. The evaluated forages presented a potential to be used on livestock pasture-based system in the Depressão Cuiabana region, specially Mulato grass and Xaraés palisadegrass.

KEYWORDS: Herbage production, cutting height, bulk density forage, productivity, leaf blade stem relation and senescence.