Morphogenetic and structural characteristics of gamba grass subjected to nitrogen fertilization and different defoliation intensities

  • Sâmara Stainy Cardoso Sanchês
  • Rosane Cláudia Rodrigues Universidade Federal do Maranhão
  • Ricardo Alves de Araújo Universidade Federal do Maranhão
  • Clésio dos Santos Costa Universidade Federal do Ceará
  • Ivone Rodrigues da Silva Universidade Federal do Piauí
  • Francisco Naysson de Sousa Santos Universidade Federal da Paraíba
  • Marcônio Martins Rodrigues Universidade Federal do Maranhão
  • Raphael Ramos Silva Universidade Federal do Maranhão
Keywords: Andropogon gayanus., Dry period, Rainy period., Residue.

Abstract

T

This study aimed to evaluate the morphogenetic, structural, and productive characteristics of Andropogon gayanus cv. ‘Planaltina’ subjected to different nitrogen fertilization levels and defoliation intensities. The experiment was done in a completely randomized design with a factorial arrangement of six nitrogen doses (0, 100, 200, 300, 400, and 500 kg N ha-1) and two defoliation intensities (15 and 30 cm). The production and structure data were grouped into rainy and dry periods, while morphogenesis data were compared only among different fertilization and defoliation intensities. The total dry forage biomass (TDFB), dry mass of leaves (DML), dry mass of stems (DMS), and dead forage dry mass (DFDM) were then determined. In addition to these variables, the morphogenetic characteristics of the plants and the numbers of tillers alive and dead were evaluated. There was no interaction (P>0.05) between the effects of nitrogen fertilization doses and the intensity of defoliation on TDFB, DML, DMS, and DFDM in both of the evaluated phases (rainy and dry). It was also observed that the rates of leaf elongation, leaf appearance, and leaf blade elongation increased with nitrogen fertilization. On the other hand, the culm elongation rate and phyllochron decreased as the dose applied increased. The defoliation intensity did not influence (P>0.05) the morphogenetic characteristics examined, nor did it affect the senescence rate of nitrogen in leaves and number of live leaves per tiller. The number of dead tillers increased linearly during the rainy period. Based on these results, to improve the efficiency of production of gamba grass it is recommended that it be managed with a defoliation intensity of 30 cm and nitrogen fertilization of 286.52 kg N ha-1 year-1.

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Published
2020-06-25
How to Cite
Sanchês, S. S. C., Rodrigues, R. C., de Araújo, R. A., Costa, C. dos S., da Silva, I. R., Santos, F. N. de S., Rodrigues, M. M., & Silva, R. R. (2020). Morphogenetic and structural characteristics of gamba grass subjected to nitrogen fertilization and different defoliation intensities. Bioscience Journal , 36(5). https://doi.org/10.14393/BJ-v36n5a2020-47944
Section
Agricultural Sciences