Canopy observation of a table grape vineyard: radiation balance, energy partitioning and CO2 fluxes

An orchard carbon fixation between 5-11 mmol m-2 s-1 has been recorded through eddy covariance technique during the summer for a table grape in Southern Italy. The total daily ecosystem exchange was equal to 2.07 g C/m2 day in 2001, and 1.68 in the warmer 2002. The latent heat of evapotranspiration was 40% Rn in 2001 and about 30% in 2002. Eddy covariance allowed to have information on the water use efficiency (WUE) of the vineyard during the two years, that was, at midday, equal to 0.0012 in 2001 and 0.0015 in 2002. WUE, determined at canopy scale, is very important mainly in those environments where water is a limiting factor and a correct irrigation schedule is necessary.