Massa de forragem e valor nutritivo de três capins em sistema silvipastoril com eucalipto

Abstract

Silvopastoral systems need to be arranged so that competition for light, water and nutrients among trees and herbaceous forage can be properly managed. Association of trees with pasture needs to be planned to assure the best animal and forestry yields. Morphological changes in shaded forages might allow them to tolerate different levels of shading. Thus, the ability to develop one or more of these acclimation mechanisms determines a species ability to grow in shaded environments and, therefore, its potential for silvopastoral systems. Hence, adjusting the best combinations among trees (density) and pasture for each climatic zone is essential success when combining forestry and cattle husbandry. This work aimed to evaluate yield and nutritional value of marandu, piatã and massai grasses in a silvopastoral system. For such, in May 2008 a Nelder Wheel was established, with 24 spokes and 22 rings, having as tree component an Eucalyptus hybrid (E. urophylla x E. grandis), clone H13. Grasses were seeded three years later, in April 2011. Forage samples were collected for each grass in the dry season (July) 2011 and 2012 and in the rainy season (January) 2012 and 2013 under tree densities of 935, 657, 461, 324 and 225 trees.ha-1. Experimental design was random blocks with four repetitions and split-plots where parcels were the Nelder Wheel arches and sub parcels were year’s seasons. Forage yield and nutritional value were evaluated through total dry matter weight (MST), leaves dry matter (MF), stems with sheath (MC) and decaying material (MMS); crude protein proportion (PB) and in vitro digestibility of organic matter (DIVMO) for grass leaves.