Potencial produtivo e qualitativo de gramíneas tropicais sob diferentes níveis de adubação nitrogenada, irrigação e época do ano

• Ano de defesa: 2006
• Autor(a) principal: Bueno, Mário Ezequiel Gomes
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual de Maringá; Brasil; Programa de Pós-Graduação em Zootecnia; UEM; Maringá, PR; Centro de Ciências Agrárias
• Palavras-chave em Português: Plantas forrageiras; Adubação nitrogenada; Irrigação; Pastagens; Digestibilidade 'in vitro'; Plantas forrageiras tropicais; Brasil.; Forage plants; Nitrogen fertilization; Irrigation; Pastures; 'In vitro'; Tropical forage plants; Brazil.; Ciências Agrárias; Zootecnia
• Link de acesso: http://repositorio.uem.br:8080/jspui/handle/1/1795

The objective of the present experiment was to compare dry matter production (DMP), leaf/stem ratio, tiller population density, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and in vitro dry matter digestibility (IVDMD) of four tropical grasses: Coast-cross (Cynodon dactylon L. Pears), Florona (Cynodon nlemfuensis), Brachiaria brizantha cv. Marandu and Brachiaria brizantha cv. Xaraés. The effect of three nitrogen levels (100, 200 and 300 kg/ha/year) with or without irrigation in two periods of the year was evaluated. In irrigated treatments, fertilization was done every two months along the year, with a total of six annual applications. In treatments without irrigation, fertilization was divided in four applications during the rainy season. The evaluation periods were from October, 2003, to April, 2004, which was considered the rainy season, and from May to September, 2004, taken as the dry season. Forage samples were cut every 27 days during rainy season (five cuttings) and 39 days during dry season (three cutting). The trial was performed in a randomized block design with a factorial scheme: 2 (with or without irrigation) x 3 (nitrogen levels) x 4 (grass species) x 2 (periods of the year), with three replications. The results were submitted to a statistic analysis according to GLM proceedings from SAS. Means were compared by the Tukey test at 5% of probability. Xaraes presented the greatest DMP, achieving 17608.4 kg/ha in rainy season and fertilized with 300 kg of nitrogen/ha. However, Cynodon grasses showed better performance for both fertilization and irrigation treatments. Brachiaria grasses presented higher results of leaf/stem ratio (P<0.05) when compared to Cynodon. Tiller population density was greater (P<0.05) for Cynodon grasses. In general, crude protein (CP) values were higher for Cynodon grasses than for Bracharia (P<0.05). On the other hand, taking in consideration NDF, Brachiaria had smaller values than Cynodon, but it didn´t happen the same way for ADF values. IVDMD values of Brachiaria were higher than the Cynodon ones.