| Registro completo |
| Provedor de dados: |
53
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| País: |
Brazil
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| Título: |
Coffee crop coefficient for precision irrigation based on leaf area index
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| Autores: |
Pereira,Antonio Roberto
Camargo,Marcelo Bento Paes de
Villa Nova,Nilson Augusto
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| Data: |
2011-01-01
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| Ano: |
2011
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| Palavras-chave: |
Coffea arábica L.
Reference evapotranspiration
Soil water balance
Planting density
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| Resumo: |
Crop coefficient (Kc) for coffee plantations was found to be linearly related to the leaf area index (L) up to 3, i.e., Kc = b L. The basic assumption is that for irrigated trees the water use per unit leaf area (ET LA) is equal to the reference evapotranspiration (ETo) expressed also on a unit leaf area basis of the reference surface (ET LA = ETo/Lo). As recommended by FAO-56 the leaf area index (Lo) for the hypothetical reference surface (grass) is equal to 2.88, then the most likely value is b = Lo-1 = 2.88-1 = 0.347. However, for L > 3 (completely covered ground surface) Kc decreased from a peak value (~1.05) tending to an asymptotic low value around 0.7 for L > 6, but the linear model gives unrealistic Kc estimates; tentatively the empirical function Kc = 1.8 L-0.5 is offered here as an initial guess due to the lack of experimental results for the interval 3.5 <L < 5.5. To become operational under commercial fields it is necessary to estimate the leaf area per coffee tree (LA, m² tree-1), and based on a very limited set of data, LA was estimated as a function of planting density (PD, trees ha-1), i.e., LA = 88.38 - 8.63 Ln (PD). Alternatively, L (< 3.4) can be computed directly as a function of canopy volume (for V < 1.2 m³).
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| Tipo: |
Info:eu-repo/semantics/article
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| Idioma: |
Inglês
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| Identificador: |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052011000400030
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| Editor: |
Instituto Agronômico de Campinas
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| Relação: |
10.1590/S0006-87052011000400030
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| Formato: |
text/html
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| Fonte: |
Bragantia v.70 n.4 2011
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| Direitos: |
info:eu-repo/semantics/openAccess
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