The objective of this study was to evaluate the morphogenic and structural characteristics of tifton 85 bermudagrass under different nitrogen doses (0, 33, 66, 100 or 133 kg/ha.year of N) and three different plant heights (30, 40 or 50 cm) at harvesting time. A split plot scheme in a completely randomized design with three replications was used. The nitrogen (N) doses stood for the portions and the haversting heights, for the subportions. The leaf appearance rate of tifton 85 bermudagrass was negatively influenced by plant height at harvesting time, but positively influenced by N dose. Leaf senescence rate and total number of leaves per tiller decreased, whereas leaf elongation rate increased with nitrogen fertilization. On the other hand, leaf senescence rates and total leaf number per tiller increased according to the plant height at harvesting time. Contrarily, the number of green leaf per tiller was not influenced by N dose or plant height at harvesting time. For the same height of 'tifton 85' bermudagrass at harvesting time, nitrogen fertilization increases tissues flux and defoliation frequency. Under intermittent defoliation conditions, 'tifton 85' bermudagrass should be harvested at 30 cm of height.
Cynodon spp; defoliation frequency; leaf; morphogenesis; senescence; tiller
