Morfogênese e dinâmica do acúmulo de forragem em capim-elefante cv. Napier submetido a alturas de resíduo pós-pastejo

• Autor(a) principal: Sousa, Braulio Maia de Lana
• Data de Publicação: 2012
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1797
• topic: Alvo de manejo; Interceptação luminosa; Altura do dossel; Management target; Light interception; Canopy height; CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::PASTAGEM E FORRAGICULTURA::AVALIACAO, PRODUCAO E CONSERVACAO DE FORRAGENS

From February to May in 2009 (experiment 1) and from December and May in 2010 (experiment 2) the effects of three post-grazing heights (30, 50, and 70 cm) on the morphogenetic and structural characteristics, and the dynamics of the forage accumulation and of the morphologic components were evaluated in pastures of Elephant grass cv. Napier when the sward reached 95% of light interception during regrowth. A complete randomized block design with three replications was used. In both experiments and for aerial and basal tillers, pastures managed with a 30 cm post-grazing height presented lower values of leaf appearance and elongation rates, of leaf lifespan, of stem elongation rate, of final leaf lamina length, and of number of live leaves per tiller. This pattern resulted in lower rates of growth of leaves and of stems, of total growth, and of forage accumulation in the pastures managed at a 30 cm post-grazing height relatively to the ones managed at 50 and 70 cm. The morphogenetic and structural characteristics slightly differ between the 50 and 70 cm post-grazing heights. Nevertheless, pastures managed at 50 cm presented the lowest rates of elongation and accumulation of stems and relatively stable rates of forage accumulation, especially in the experiment 2, in comparison to the ones manages at 70 cm, suggesting that this post-grazing height would be the most indicated one. The strategy of decapitating the majority of the apical meristems in the first grazing (experiment 2) resulted in relatively more stable values of morphogenetic and structural characteristics and in lower stem accumulation rates, suggesting the need for a thorough control of the elevation of the apical meristems in the first cycle of growth in the spring as a way of assuring the control of the structure of the pastures and forage production with elevated leaf proportion.