Resumo

CASTAGNARA, D.D. et al. Nutritional value and structural characteristics of tropical grasses under nitrogen fertilization. Arch. zootec. [online]. 2011, vol.60, n.232, pp.931-942. ISSN 1885-4494.  https://dx.doi.org/10.4321/S0004-05922011000400010.

The experiment was carried out in the experimental farm of Unioeste, Marechal Candido Rondon, PR, Brasil, with the objective of evaluate the effects of increasing N doses under structural features and chemical composition of three tropical forage grasses. The experimental design used was of randomized blocks in factorial scheme 3x4, with three tropical forages (Panicum maximum cvs. tanzânia and mombaça, and Brachiaria sp. cv. mulato) and four doses of N (0; 40; 80 and 160 kg/ha) taking urea as N sources. Were evaluated: canopy height leaf/stem ratio, diameter and height of pseudoculm, and contents of crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and mineral matter (MM). There was effect of N doses on canopy height and height of pseudoculm that showed quadratic behavior. The leaf/stem ratio responded negatively to N doses, while the diameter of pseudoculm was influenced only by forages. For CP content was found significance of interaction of factors, being that in dose of 80 kg/ha of N the Tanzania grass was higher than the other. The contents of NDF responded of form quadratic to N doses, while the contents of ADF were influenced only by forages.

Palavras-chave : Crude protein; Panicum maximum; Brachiaria sp.

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