Morphogenesis and structural characteristics of regrowth of Brachiaria brizantha cv. Marandu assigned to three nitrogen levels

An experiment was arranged in a randomized blocks design, in a 3 x 8 factorial scheme, three nitrogen (N) levels (0, 20 e 40 mg dm(-3) week(-1) of N) and eight regrowth ages (0, 2, 4, 8, 16, 24, 32 and 48 days after the standardized harvest) in pots in greenhouse, with three replicates for each treatment, to evaluate the morphogenesis (leaf appearance rate [TA(P)F] and leaf elongation rate [TA(1)F]) and structural characteristics (average leaf length [CMF], number of alive leaves tiller(-1) [NFVP], average tiller weight [PMP] and density tiller [DP]) of Brachiaria brizantha cv. Marandu. TA(p)F showed significant effect as the nitrogen level increased. Plants that received 40 mg dm(-3) week(-1) of N showed phyllochrons inferior (6.99 days leaf(-1)) than those observed in the control (12.20 days leaf(-1)). TA(1)F was very sensible to the N application and increased as the N level increased (185.24 and 264.32%, respectively, for plants that received 20 and 40 mg dm(-3) week(-1) of N). CMF showed positive and significant effect, as the nitrogen level increased. N levels and regrowth age showed significant and positive effect on NFVP and PMP. Although the higher NFVP, plants that received N levels had higher loss by senescence. The quantitative factors also showed significant and positive effect on DP.