Morphogenic and structural characteristics of guinea grass pastures submitted to three frequencies and two defoliation severities

Revista Brasileira de Zootecnia

Rodrigo Amorim Barbosa²  Domicio Do Nascimento Júnior¹  Hélio Henrique Vilela¹  Sila Carneiro Da Silva¹  Valéria Pacheco Batista Euclides²  André Fischer Sbrissia¹  Braulio Maia De Lana Sousa¹ 

[1] ,EMBRAPA CNPGCCampo Grande MS

关键词: canopy height;    grazing management;    light interception;    Panicum maximum;    altura do dossel;    interceptação de luz;    manejo do pastejo;    Panicum maximum;   

DOI  :  10.1590/S1516-35982011000500002

来源: SciELO

【 摘 要 】

It was evaluated the morphogenic and structural characteristics of guinea grass under rotational at three grazing intervals and two defoliation intensities. Grazing intervals corresponded to the time needed by the forage canopy to reach 90, 95 or 100% of incident light interception during regrowth and they were evaluated combined to two defoliation severities (post-grazing conditions, 25 and 50 cm of height), being allocated to experimental units according to a complete randomized design, with three replicates and 3 × 2 factorial arrangement. The experiment was conducted from July 2003 to May 2004. For evaluation of morphogenetic and structural characteristics, ten tillers per experimental unit were selected. Morphogenetic and structural characteristics were strongly influenced by seasons of the year inasmuch as leaf elongation rate increased 3.5 fold from winter to summer. In addition to year season effect, there was also an effect of defoliation frequencies on tiller population density, which was greater in the defoliation period corresponding to 90% of light interception, especially if evaluated in relation to the interval corresponding to 100% of light interception. Defoliation frequency is determinant in expression of phenotypic plasticit, acting on the control of stem elongation.

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