Valor nutritivo do capim-braquiária e do amendoim forrageiro submetidos ao sombreamento

Abstract

The chemical characteristics and digestibility of signalgrass (Brachiaria decumbens cv. Basilisk) and forage peanut (Arachis pintoi cv. Amarillo) were evaluated in response to different shade levels (0, 50 and 70%) with the objective of determine changes in nutritive value of these forage species. Treatments were arranged in four replicates of a randomised complete block design. There were three and two harvests within the experimental period, for signalgrass and forage peanut, respectively. The dry matter content of both species was reduced (p<0.05) with increasing shade levels. Forage peanut and signalgrass showed increment (p<0.05) in crude protein content with shading. Nevertheless, the increment was not significant in the second harvest of forage peanut. The neutral detergent fiber (FDN) and acid detergent fiber (FDA) contents of forage peanut increased (p<0.05) with increasing shade levels, in both harvests. In the first harvest of signalgrass, increasing shade levels does not caused significant alterations (p>0.05) in the cell wall constituents. On the other hand, in the second harvest it was observed a linear reduction (p<0.05) in FDN and FDA contents, with shading. In the third harvest of signalgrass shading promoted increment (p<0.05) in FDA content. The in vitro dry matter digestibility of both species was not significantly affected (p>0.05) by treatments. The variation in macronutrients (Ca, Mg, P and K) concentration was not consistent between species and harvests, but in general the concentrations of the minerals evaluated were higher under shade. The data indicated that signalgrass and forage peanut have great potential to produce quality forage in silvopastoral systems.