Estudo de gramíneas forrageiras tropicais em diferentes idades

Abstract

The experimentwas conducted in the Animal Science Departmentofthe Universidade Federal de Lavras from November, 2000 to May, 2001 with the objective of comparing four cutting ages (28, 42, 56 and 70 days) on the yield and nutritive value of the grasses Coastcross (Cynodon dactylon (L.) Pers. cv. Coastal x Cynodon nlemfuensis Vanderyst var. robustus), Tifton 68 (Cynodon spp) and Tifton 85 (Cynodon spp) in the growing seasons of these years. Establishment fertilization with the application of 120 kg/ha of P205, as simple superphosphate, 150 kg/ha of N, as ammoniumsulfate, and 60 kg/ha of K20, as potassium chloride was performed. The randomized block design in a split plot scheme and five replicates. Was utilized, regardless of the cultivars studied, a quadratic increase was recorded in dry matter yield with the advance of the maturity stage from 28 to 70 days old, values of 2.15 to 11.09 ton/ha being obtained. Dry matter content increased in a linear way with the advance of the regrowth age, ranging from 23.96 to 26.91% from 28 to 56 days. Crude protein contents presented a linear decrease with the advance of the maturity age, ranging from 17.18 to 11.04% at 28 and 70 days of growth. Contentsof neutral detergent and acid detergent fíber presented a linear and quadratic behavior with the increase ofcut age, values of82,19 e 81,82% and 36,75 and 39,36%, at 56 and 70 days of maturity, respectively. , being obtained The "zw vitro" digestibility coefficients of dry matter decreased in a quadratic way with advancing maturity age, ranging from 65.11 to 51.50% at 28 and 70 days. A quadratic decrease was recorded for the contents of P, Mg, K and S with the increase of cut age, whereas Ca presented a linear increase. For ali the grasses investigated, the best cut age is when maturity is situated between 42 and 56 daysin which onecanfind a good yieldand nutritive valueof the forage grown.