Abstract

DA SILVA, T.C. et al. Morphogenesis and structure of Brachiaria decumbens submitted tocut management and nitrogen fertilization. Arch. zootec. [online]. 2012, vol.61, n.233, pp.91-102. ISSN 1885-4494.  https://dx.doi.org/10.4321/S0004-05922012000100010.

Aimed to evaluate the morphogenetic and structural characteristics of the pasture of Brachiaria decumbens, subjected to several intensities and frequencies of cutting and nitrogen fertilization. Experimental design was randomized blocks in split plots, whit a 2 x 2 factorial arrangement relating to combinations of two cutting heights (40 and 50 cm) and two heights of residue (15 and 25 cm) at the plots and nitrogen fertilization (with or without nitrogen) in sub-plots, with four replications. Mophogenetic variables evaluated were: leaf elongation rate (LER), stem elongation rate (SER), leaf appearance rate (LAR), leaf senescence rate (LSR) and phyllochron; and structural features were: number of basal tillers (NBT), total number of leaves (TNL), number of leaves appeared (NLAp), number of dead leaves (NDL), number of alive leaves (NAL) and final leaf length (FLL). 100 kg N/ha allowed increase (p<0.10) on LER of 31.58% and 126.32% respectively for residues 15 and 25 cm. The NBT compared to cutting heights (40 to 50 cm) were affected (p<0.10) only with the use of nitrogen fertilizer, with average of 145.62 tillers/m² in 50 cm cut height. Residue height of 25 cm combined with cut height 40 cm increase leaf elongation rate and number of basal tillers, reducing expansion time, without changing other structural characteristics of the pasture.

Keywords : Leaf length; Phyllochron; Management; Number of leaves; Tiller.

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