Light interception, chemical, and productive characteristics of elephant grass subjected to different cutting intervals

Abstract

This study aimed to evaluate the interception of light (%IL), leaf area index (LAI), and the chemical and productive characteristics of elephant grass (Pennisetum purpureum Schum) under different defoliation frequencies (30, 45, 60, 75, and 90 days after cutting). The experimental design was completely randomized with five replications and five treatments (cutting frequencies). The chemical composition was analyzed in a factorial arrangement 2 ×5 (two fractions: leaf and stem, and five defoliation frequencies). The pattern of variation in IL and LAI in function of the frequency of cutting was ascending order. The maximum values of %IL and LAI occurred at 75 and 90 days after cutting with 98.46%; 98.72% (%IL) and 7.08; 8.10 (LAI), respectively. There was no effect of cutting frequency on the total yield of forage, leaf production, generation of stem and dead material, tillers alive, dead tillers and height. Only the leaf/stem ratio was not influenced (P > 0.05) among the factors studied. The frequency of cutting influenced (P < 0.05) the chemical composition, where decreased cutting frequency significantly increased the levels of dry matter, neutral detergent fiber, acid detergent fiber, cellulose, and ash in two fractions evaluated (leaf and stem); the crude protein content showed a decline from the moment the frequency of cutting was increased. The LAI, and productive and chemical characteristics of elephant grass were influenced by increased frequency of cutting. Limiting the cutting of the grass to 60 days implies an optimal point of production and quality.