|Authors: ||G. Selles, R. Ferreyra, C. Aspillaga, S. Ortega-Farias, P. Villagra, V. García de Cortázar|
|Keywords: ||evapotranspiration, crop coefficient, energy balance, FAO Penman-Monteith, table grape|
During the 2008-2009 season, net radiation (Rn) and soil heat flux (G), sensible heat flux (H) and latent heat flux (LE=λ ETc where ETc is vine evapotranspiration and λ is the latent heat of vaporization) were measured on a drip-irrigated ‘Thompson Seedless’ vineyard trained on an overhead trellised system (“parronal español”). The experiment was located in Calle Larga, Aconcagua valley, Chile (32°52’40’’ S, 70°37’45’’ O, 795 m a.s.l.). LE and H were obtained from an eddy covariance system.
The reference evapotranspiration (ETo) was calculated using the FAO-Penman-Monteith model.
Results indicated that the closure (ratio of LE+H to Rn-G) was 0.91 in November ‘08 and 0.82 in January ‘09. At flowering (74% solar interception), the mean ratios of LE, H and G to Rn were 0.53, 0.26 and 0.11, respectively.
At veraison (98% solar interception) LE, H and G were 0.81, 0.01 and 0.1 of Rn respectively.
Also, an increase of crop coefficient (Kc = ETc/ETo) values from October to mid-November was observed.
Afterwards, it was almost stable until mid-January when an increase was again observed.
A maximum Kc value of 1.3 was reached at veraison.
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