|Abstract||The State of Acre has a population of 500 thousand inhabitants, with a territorial extension of 152.589 km2, which represents 1,79% of the National Territory and it is located in the Western part of the Brazilian Amazon, occupying 3,16% of this region (IBGE, 1997). In the State of Acre, the predominant ecosystem is the tropical rainforest, with high diversity of species per hectare. In these areas, the main economic activity in the last century has been the extraction of the latex of the rubber trees (Hevea brasiliensis) and the collection of Brazil nut (Bertholletia excelsa)). However, in the last 30 years, the disruption of the extractive system in the “seringais” (native rubber states), the creation of settlement projects and the expansion of cattle ranching activities transformed the economy of the primary sector of Acre (Valentim 1989; Valentim and Moreira 1994).
Tree species generally grow more than forage species, so that when they are established in the same area, the first ones interfere in the passage of light for the herbaceous extract under the tree canopies. In most of the situations, the rate growth of the pastures is lower below the tree canopy than in full sun. However there are differences among the forages, because some are more tolerant than others when submitted to lower light conditions (Pezo and Ibrahim 1998).
There have been growing pressures for reforestation, particularly with multiple use trees in silvipastoral systems which vary according the environmental, social e economic characteristics of the different regions of the world. Silvipastoral systems are land use alternatives that can be ecologically and economically viable in the Amazon. In order to achieve these goals, these systems should be well planned, with the selection of the most appropriate tree species being one of the most important aspects in this process. Successful associations of trees and forage species depend on a careful evaluation of the interactions among the components of the ecosystem.
The objective of this study was to evaluate the effect of shading of two species of native tree legumes on chemical composition of forage produced by Penisetum purpureum. |