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Crop coefficients and transpiration of a super intensive Arbequina olive orchard using the dual Kc approach and the Kcb computation with thr fraction of ground cover and height
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Resumo(s)
The SIMDualKc model was used to simulate crop water requirements for a super high
density olive orchard in the region of Alentejo, Portugal. This model uses the dual crop coefficient
approach to estimate and partitioning the actual crop evapotranspiration (ETc act) and therefore to
perform the soil water balance. The model was calibrated with 2011 tree transpiration using trunk
sap flow measurements and was validated using similar data from 2012 and tested with 2013 data.
Low root mean square errors (RMSE < 0.53 mm d 1) and acceptable modelling efficiency indicators
(EF > 0.25) were obtained. Further validation was performed comparing modelled ETc act with eddy
covariance measurements. These indicators support the appropriateness of using SIMDualKc to guide
irrigation management. The basal crop coefficient (Kcb) curves obtained with SIMDualKc for those
3 years were compared with the Kcb values computed with the Allen and Pereira approach (A&P
approach) where Kcb is estimated from the fraction of ground cover and plant height considering an
adjustment factor for crop stomatal control (Fr). Fr values were obtained through a trial and error
procedure through comparing the Kcb estimated with this approach and with SIMDualKc. The Kcb
curves obtained by both methods resulted highly correlated, which indicates that the A&P approach
may be used in the irrigation management practice to estimate crop water requirements. Results
of performing the soil water balance with SIMDualKc have shown that soil evaporation is a large
fraction of ETc act, varying between 41% and 45% for the 3 years under study. Irrigation, applied
with a drip system, represented 39 to 56% of ETc act, which shows the great importance of irrigation
to achieve the water requirements of super intensive olive orchards. Nevertheless, the analysis
has shown that the irrigation management adopted at the orchard produces a water deficit larger
than desirable, with a ratio of ETc act to non-stressed crop evapotranspiration (ETc) varying from
70% to 94% during the mid-season, when that ratio for a eustress irrigation management could be
around 90%
Descrição
Article
Palavras-chave
evapotranspiration irrigation density coefficient dual crop coefficients row crops
Contexto Educativo
Citação
Water 2019, 11, 383
Editora
MDPI