Canopy observations of a table grape vineyard:: Radiation balance, energy partitioning and CO2 fluxes

An orchard carbon fixation between 5-11 mu mol m(-2) S-1 was recorded through the eddy covariance technique during the summer for a table g ape in southern Italy. The total daily ecosystem exchange was equal to 2.07 g C/m(2)/day in 2001 and 1.68 in 2002, which was warmer. The latent heat of evapotranspiration was 40% Rn in 2001 and about 30% in 2002. Eddy covariance allowed estimation of the water use efficiency (WUE) of the vineyard, which averaged 0.0012 in 2001 and 0.0015 in 2002 at mid-day. WUE, determined at the canopy scale, is very important in those environments where water is a limiting factor and a correct irrigation schedule is necessary.