Growing dynamics and nutritive value of a Lolium perenne L. pasture under different frequencies of defoliation: Autumn-Winter season

Abstract

The study was carried out in the autumn-winter season in Valdivia, Región de Los Rios, Chile. Twenty-seven mini-swards of Lolium perenne L. cv. Impact were used and established in 125 L containers (0.181 m2). A complete randomized block design was used with nine treatments and three blocks. Treatments were given by nine frequencies of defoliation, which were 1- 1.5- 2- 2.5- 3- 3.5- 4- 4.5- 5 leaves per tiller. Measurements were made every three days on marked tillers to determine rate of leaf appearance, leaf elongation rate and tiller appearance rate. At each cut, dry matter yield was measured and forage was collected for chemical composition analysis. Results were subjected to an ANOVA and Waller-Duncan test for comparison of means. Regression analyses were made between the defoliation frequency and the evaluated variables. Results showed that the phyllochron was independent of the defoliation frequency and varies from 11 to 25 days, depending on season (Autumn-Winter). The defoliation frequency significantly (p <0.01) modified the elongation of leaves of L. perenne and the herbage mass produced, being higher in the treatments less frequently defoliated. It was not found a significant effect (p >0.05) of the defoliation frequencies on tiller density, neither tiller appearance. The nutritive value was significantly modified by the defoliation frequency.