Evapotranspiration of an hedge-pruned olive orchard in a semiarid area of NE Spain

Abstract

The evapotranspiration of hedge-pruned olive orchards (Olea europaea L. cv. Arbequina) was measured under the semiarid conditions of the middle Ebro River Valley in a commercial olive orchard (57 ha) during 2004 and 2005. No measured ETc values for this type of olive orchards have previously been reported. An eddy covariance system (krypton hygrometer KH20 and 3D sonic anemometer CSAT3, Campbell Scientific) was used. The eddy covariance measurements showed a lack of the energy balance closure (average imbalance of 26%). Then sensible and latent heat (LE) flux values were corrected using the approach proposed by Twine et al. (2000) in order to get daily measured olive evapotranspiration (ETc) and crop coefficient (Kc) values. The highest measured monthly ETc averages were about 3.1�3.3 mm day-1, while the total seasonal ETc during the irrigation period (March�October) was about 585 mm (in 2004) and 597 mm (in 2005). Monthly Kc values varied from about 1.0 (Winter) to 0.4�0.5 (Spring and Summer). These Kc values were similar to Kc values reported for round-shape canopy olive orchards, adjusted for ground cover, particularly during late Spring and Summer months when differences among measured and published Kc values were about less than 0.1.