Crescimento, produção e valor nutritivo do capim-piatã em sistema agrossilvipastoril com duas densidades de eucalipto

Abstract

The study was conducted at Embrapa Beef Cattle, Campo Grande, Mato Grosso do Sul State, with the objective of evaluating the growth and nutritive value of grass in Piata agrosilvopastoral system with two densities of eucalyptus: 22 and14 meters between rows of eucalyptus. The experimental design was a randomized block design in a split plot design with four replications during winter. The plots treatments were the Integration Cattle Farming Forest at systems 1 and 2, which consisted of Brachiaria brizantha piatã planted after soybean harvest in the cropping system in consortium with eucalyptus (Eucalyptus urograndis) with 2m spacing between trees and between rows of 22 and 14 m, and the subplot treatments, points A, B, C, D and E, which were arranged between the rows of trees. The forage growth was evaluated, performing sampling 50 days after emergence, and every 15 days at each point (A, B, C, D and E) within each plot. During this period, also proceeded to analyze the morphogenesis of grass for 60 days with weekly reviews 5 tillers were marked within each section (A, B, C, D and E) within each portion. The variables analyzed were canopy height, canopy cover, plant density, leaf area index, leaf/stem ratio, dry matter production, Spad index, percentage of shade and morphogenesis (final leaf length, leaf appearance rate, rate of leaf elongation, stem elongation rate, lifespan of leaves and phyllochron number of live leaves per tiller). After the establishment of forage, which occurred at 110 days, the first court was held, where the entire sample was collected from each sub plot for the evaluation of the total production of forage and morphological components of nutritional assessment. There was a significant density of Eucalyptus for phyllochron variable. For the lifespan of leaves and plant density did not affect variable and this is not a variable influenced by shading. The dry matter content of the forage was the only variable that was higher in the near trees, where the highest percentage of shading points were found. The other morphogenetic and structural variables evaluated had a strong negative influence of shading, with lower values at the closest points to the trees. Treatment with 22 meters of distance between rows of trees, with a density of 227 eucalyptus trees/ha showed the best results of nutritional composition