Evaluation of single and dual crop coefficients over a drip-irrigated Merlot vineyard (Vitis vinifera L.) using combined measurements of sap flow sensors and an eddy covariance system
Article first published online: 22 APR 2013
© 2013 Australian Society of Viticulture and Oenology Inc.
Australian Journal of Grape and Wine Research
Volume 19, Issue 2, pages 249–260, June 2013
How to Cite
Poblete-Echeverría, C.A. and Ortega-Farias, S.O. (2013), Evaluation of single and dual crop coefficients over a drip-irrigated Merlot vineyard (Vitis vinifera L.) using combined measurements of sap flow sensors and an eddy covariance system. Australian Journal of Grape and Wine Research, 19: 249–260. doi: 10.1111/ajgw.12019
- Issue published online: 30 MAY 2013
- Article first published online: 22 APR 2013
- Manuscript Accepted: 25 JAN 2013
- Manuscript Revised: 3 NOV 2012
- Manuscript Received: 21 MAR 2012
- FONDECYT POSTDOCTORAL. Grant Number: N°3100128
- CONICYT. Grant Number: N°79090035
- FONDECYT. Grant Number: 1071040
- Universidad de Talca
- actual evapotranspiration;
- dual crop coefficient;
- eddy covariance system;
- sap flow sensor;
- single crop coefficient
Background and Aims
Irrigation is one of the most important viticultural practices in semi-arid regions. For this reason, the Food and Agriculture Organization's Irrigation and Drainage Paper No. 56 single and dual crop coefficient approaches were evaluated to estimate actual evapotranspiration (ETa) over a drip-irrigated Merlot vineyard.
Methods and Results
Vine transpiration was measured using sap flow sensors, and ETa was measured by an eddy covariance system. Soil evaporation was calculated as the difference between ETa and sap flow sensors. Reference evapotranspiration (ETo) was calculated using the Penman–Monteith equation. This information was used to evaluate single (Kc) and dual crop coefficients [Kcb and Ke] approaches during the 2007/08 and 2008/09 grapevine growing seasons.
Results indicated that vine transpiration is the most important component of ETa for a drip-irrigated Merlot vineyard trained on a vertical shoot-positioned system. In midseason, the observed values of single crop coefficients and Kcb were lower by 11 and 19% than those recommended by the Food and Agriculture Organization's Irrigation and Drainage Paper No. 56 for grapevines, respectively. The application of site-specific Kcb values reduced the error in the estimation of ETa by about 10%.
Significance of the Study
The study indicates that the use of sap flow sensors could be an alternative method for obtaining site-specific Kcb values for vineyards under field conditions.