Gas exchange in massai grass under five nitrogen fertilization levels during establishment and regrowth.

The objective of this study was to evaluate gas exchange in the massai grass during establishment and regrowth cycles in a greenhouse, using five nitrogen (N) fertilization levels. A completely randomized split-plot design of five nitrogen levels (0; 150; 300; 450 and 600 mg N?dm-3 of soil) was empl...

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Detalles Bibliográficos
Autores: LOPES, M. N., LACERDA, C. F. de, CÂNDIDO, M. J. D., POMPEU, R. C. F. F., SILVA, R. G. da, LOPES, J. W. B., FERNANDES, F. R. B., BEZERRA, F. M. L.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2011
País:Brasil
Institución:Empresa Brasileira de Pesquisa Agropecuária (Embrapa)
Repositorio:Repositório Institucional da EMBRAPA (Repository Open Access to Scientific Information from EMBRAPA - Alice)
Idioma:portugués
OAI Identifier:oai:www.alice.cnptia.embrapa.br:doc/899510
Acceso en línea:http://www.alice.cnptia.embrapa.br/alice/handle/doc/899510
Access Level:acceso abierto
Palabra clave:Fortaleza
Variedade Massai
Ceará
Panicum maximum
Pastagem
Gramínea forrageira
Chlorophyll
Photosynthesis
Brazil
Descripción
Sumario:The objective of this study was to evaluate gas exchange in the massai grass during establishment and regrowth cycles in a greenhouse, using five nitrogen (N) fertilization levels. A completely randomized split-plot design of five nitrogen levels (0; 150; 300; 450 and 600 mg N?dm-3 of soil) was employed with the N levels as plots, and the cycles (establishment, regrowth 1 and 2) as subplots, evaluated with five replicates. We evaluated leaf transpiration (E), leaf temperature (TFOL), leaf photosynthesis rate (A), leaf carbon dioxide concentration (Ci), stomatal conductance (gs), photosynthesis/transpiration ratio (A/E), photosynthesis/conductance ratio (A/gs), chlorophyll relative index (CRI), and nitrogen sufficiency index (NSI). Growth cycles influenced all physiological characteristics, except for NSI. N fertilization levels affected TFOL, A, CRI and NSI variables, whereas for gs, E, Ci, A/E and A/gs it did not occur. A increased from 6.38 to 10.33 μmol?m-2. s-1, at levels 0 and 600 mg N?dm-3 of soil, respectively. Gas exchange in the massai grass was favored by nitrogen fertilization, since the cycles amended these characteristics of the grass.

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