文摘
To evaluate the partitioning of net radiation (R n) and actual evapotranspiration (ET a), measurements of R n, sensible heat flux (H), soil heat flux (G), latent heat flux (LE), reference evapotranspiration (ET o), transpiration (T p) and soil evaporation (E s) were taken during the 2009/2010 and 2010/2011 growing seasons on a flat and uniform olive (cv. Arbequina) orchard, located in the Pencahue Valley, Región del Maule, Chile (35°23′ LS; 71°44′ LW; 96 m above sea level). Olive trees were trained on a triangular hedgerow system with a plant density of 1333 trees ha−1 (superintensive). An eddy covariance system, sapflow sensors and microlysimeter were used to measure ET a, T p and E s, respectively. Results indicated that the eddy covariance measurements showed a lack of the energy balance closure of 12.8 %. Values of LE, H and G were between 28–47, 34–68 and 2–6 % of R n, respectively, while ratios of T p and E s to ET a ranged between 0.64–0.74 and 0.26–0.36, respectively. During two growing seasons, the single crop coefficient (K c = ET a/ET o) was between 0.27 and 0.66, while the dual crop coefficient (T p/ET o + E s/ET o) ranged between 0.26 and 0.56. According to these results, H and T p were the main component of R n and ET a, respectively, for the particular conditions of the drip-irrigated olive orchard with a fractional cover of 30 % and wetted area of 4.5 %.