Estimation of actual evapotranspiration over a rainfed vineyard using a 1-D water transfer model: A case study within a Mediterranean watershed

Mauricio Galleguillos (1) , Frédéric Jacob (2) , Laurent Prevot (2) , Carlos Faúndez (3) , Aline Bsaibes (4)

1 Centre for Climate and Resilience Research
2 UMR LISAH - Laboratoire d'étude des Interactions Sol - Agrosystème - Hydrosystème
3 Soil Physics and Land Management Group
4 ITK

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.

Mots clés: soil water balance; simulation models; water table; heterogeneous landscape; HYDRUS-1D; vadose zone

Mots clés: évapotranspiration; bilan hydrique du sol; modèle de simulation; zone méditerranéenne; zone vadose; vitis vinifera; hydrus 1d

Domaines: Sciences du Vivant [q-bio]

Mauricio Galleguillos, Frédéric Jacob, Laurent Prevot, Carlos Faúndez, Aline Bsaibes. Estimation of actual evapotranspiration over a rainfed vineyard using a 1-D water transfer model: A case study within a Mediterranean watershed. Agricultural Water Management, 2017, 184, pp.67-76. ⟨10.1016/j.agwat.2017.01.006⟩. ⟨hal-01607897⟩