Resumo

ACERO-CAMELO, Amanda; PABON, Martha L.; FISCHER, Gerhard  e  CARULLA-FORNAGUERA, Juan Evangelista. Optimum harvest time for Kikuyu grass ( Cenchrus clandestinus ) according to the number of leaves per tiller and nitrogen fertilization. Rev. Fac. Nac. Agron. Medellín [online]. 2020, vol.73, n.3, pp.9243-9253. ISSN 0304-2847.  https://doi.org/10.15446/rfnam.v73n3.82257.

To determine the optimum harvest time of kikuyu grass (Cenchrus clandestinus (Hochst. ex Chiov.) Morrone), according to the number of leaves per tiller and nitrogen fertilization level, an experiment was carried out under greenhouse conditions using a 4×4 factorial design. The factors were the number of leaves per tiller (3, 4, 5, 6 leaves) and level of nitrogen (N) fertilization (0, 50, 100,150 kg of Nitrogen ha-1 year-1). Dry matter (DM) yield and nutritional quality were determined. Additionally, the independent effect of nitrogen fertilization on undisturbed height, tiller density, and the phyllochron were evaluated. When the number of leaves per tiller increased (3 to 6), the leaf yield and dead forage also increased (P<0.05). The leaf-stem ratio (L:S) remained constant (P>0.05) among the number of leaves. Green forage-dead forage ratio (GF:DF) decreased (P<0.05) with a higher number of leaves per tiller. The concentration of crude protein (CP) decreased while the concentration of neutral detergent fiber (NDF) increased with an increment of the number of leaves per tiller (P<0.05). Nitrogen fertilization increased the undisturbed height, the density of tillers, DM yield from leaves, stems and green forage, GF:DF, and CP (P<0.05) while NDF decreased (P<0.05). The phyllochron was higher without N fertilization. The effects of the number of leaves per tiller and N fertilization on the most variables measured were independent of each other. However, due to an increment in DM yield caused by N fertilization, the pasture can be defoliated with fewer leaves per tiller, increasing defoliation frequency and improving forage quality.

Palavras-chave : Defoliation frequency; Leaf stage; Leaf to stem ratio; Pennisetum clandestinum.

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