Estimation of actual evapotranspiration over a rainfed vineyard using a 1-D water transfer model: A case study within a Mediterranean watershed
2017
Galleguillos, Mauricio | Jacob, Frédéric | Prevot, Laurent | Faúndez, Carlos | Bsaibes, Aline | Centre for Climate and Resilience Research ; Universidad de Chile = University of Chile [Santiago] (UCHILE) | Laboratoire d'étude des Interactions Sol - Agrosystème - Hydrosystème (UMR LISAH) ; Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro) | Soil Physics and Land Management Group ; Wageningen University and Research [Wageningen] (WUR) | ITK | This study benefited from grants by the Chilean NationalCommission for Scientific and Technological Research, and by theFrench National Institute for Agricultural Research
The current study aims to evaluate the capabilities of soil water balance modeling to estimate ET for very different conditions of rainfed grapevine water status, within a vineyard landscape that depicts heterogeneities in canopy, soil and water table conditions. We calibrated the HYDRUS-1D model against measurements of the soil moisture profile within seven contrasted sites, we validated HYDRUS-1D sim-ulations against ET estimates derived from eddy covariance (EC) measurements within two contrasted sites, and we analyzed the temporal dynamics of the HYDRUS-1D ET simulations throughout almost two growth cycles for the seven sites. The calibration of HYDRUS-1D was correctly achieved, with a relative RMSE of 20% on average. Validation of HYDRUS-1D simulations against EC measurements was satisfactory, with RMSE values of about 40 W m−2 at the hourly timescale and 0.5 mm d−1 at the daily timescale. HYDRUS-1D was able to provide consistent time series of ET within the seven contrasted sites and throughout the two growth cycles. We conclude that HYDRUS-1D simulations can be used as an alternative to EC measurements within rainfed vineyards, to alleviate experimental efforts for device cost and maintenance. Further, HYDRUS-1D simulations can be used for characterizing spatial variabili-ties and temporal dynamics, assessing impact of pedological conditions and land use on ET, or validating remote sensing retrievals over regional extents.
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