Atributos agronômicos de gramíneas forrageiras exóticas sob pastejo no agreste pernambucano

Abstract

Grasses are important forage resources, it constitutes feed for ruminants with competitive costs. Thus, evaluation of species adapted to the ecological conditions of the area to be explored is of fundamental importance to the success of animal production system. An experiment was conducted at the Experimental Station Caruaru belonging to the Agronomic Institute of Pernambuco-IPA, aiming to evaluate productive characteristics of exotic grasses. The experimental design was a randomized block design with four replications. The experimental plots were represented by pickets 25 m² (5 m x 5 m), being 9 m² (3 m x 3 m) of useful area. The experimental treatments were three species of exotic grasses (buffel grass – Cenchru sciliaris L.; pangola grass- Digitariapentzii stent and the spontaneous genotype of the region of Panicum maximumJacq.); beyond the control treatment, that consisted of the region's spontaneous species. The evaluations were conducted from March 2011 to September 2011, totalizing six grazing cycles. Grazing cycles were 35 days, with a day of grazing and 34 days of rest. It was used intermittent stocking, with cattle being used as grazing animal in “mob grazing”, seeking a 20 cm height of residue post-grazing. It were evaluated the herbage mass, accumulation and herbage accumulation rate, canopy height, desirability, number of tillers, losses due to grazing, litter accumulation, botanical composition and soil covering. The data were subjected to analysis of variance with repeated time measures. For the variable height, it was found significant difference for both, species and grazing cycles, having in the first cycle (March) the Panicum obtained greater height with 120.6 cm. For variables as desirability, number of tillers, and soil covering, the pangolão grass was superior to the other species. There was no significant difference (P <0.05) for herbage mass and herbage accumulation between treatments. The buffel grass proved to be very susceptible to invasive plants, the pangolão grass proved to be the most promising for being utilized in the Agreste of Pernambuco.