Estratégias de manejo do capim-elefante cv. Napier sob pastejo rotativo

• Autor(a) principal: Monteiro, Hélida Christhine de Freitas
• Data de Publicação: 2011
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1786
• topic: Morfogênese; Alvo de manejo; Interceptação luminosa; Morphogenesis; Target management; Light interception; CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::PASTAGEM E FORRAGICULTURA

Grazing management strategies should explore and use adaptive resources and establish optimal management ranges for foraging species, which constantly suffer interference from both the animals that graze them and environmental factors. As a result, such species need adaptation mechanisms so that they can survive in the system. This study aimed to analyze and describe the effects of grazing intensities, represented by different post-grazing heights coupled with the frequency of defoliation of 95% of the light intercepted by the foraging sward, on structural characteristics, forage production and tillering dynamics in elephant grass cv. Napier pastures. Two experiments were conducted in an area of the Department of Animal Science, Federal University of Viçosa, between February-May 2009 (experiment 1) and November 2009-May 2010 (experiment 2). The treatments consisted of combinations of three conditions of post-grazing height (residues of 30, 50 and 70 cm) with sward light interception (LI) of 95% during regrowth. The treatments were allocated to experimental units (paddocks of 400 m2), according to a randomized complete block design with three replications. In experiment 1, frequency input of the first grazing animals was in accordance with the 95% LI, while in experiment 2, in the first grazing alone, the frequency was in accordance with the height of the apical meristems at the level of the residue in each experimental unit. Based on the positive relationship between light interception and height, the two experiments showed that the post-grazing heights were very close to the intended goal, and so was light interception in the pre-grazing period. The pastures showed a number of cycles which vary depending on the residue and the length of each grazing cycle. Structural characteristics, mass production and tillering dynamics were assessed by means of factor analysis. It was observed that the pastures with 70 cm residues favor the accumulation of dry matter, but they also alter morphological composition, favoring the accumulation of stems and dead material. Pastures with 30 cm-residues favor the emergence of competing plants. The mass accumulation rates are influenced by the amount of leaves in the post-grazing period. Elephant grass cv. Napier has the capacity to adapt to different rotational grazing strategies by changing its structure to maintain continuity and stability of the population.