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United States Department of Agriculture

Agricultural Research Service

Research Project: Separating Components of Evapotranspiration to Improve Efficiency in Vineyard Water Management Project Number: 3625-11610-001-04
Project Type: Reimbursable

Start Date: Dec 01, 2009
End Date: Nov 30, 2013

Objective:
1) Develop a measurement/modeling technique to identify components of evapotranspiration in temperate and semi-arid vineyard systems. 2) Define strategies for excess water removal and/or water conservation in vineyards for moist temperate regions of the Southeastern U.S. (North Carolina). 3) Define strategies for water conservation in vineyards for semi-arid regions of Israel (Arad valley).

Approach:
Water management could be significantly improved if the components of evapotranspiration in the vineyard systems (i.e. vines, and grassed and/or bare interrows) could be quantified and appropriately manipulated. The components of the vineyard system (vines, grass, and soil) have seasonally variable water loss from transpiration and/or evaporation, and the natural water supply from rainfall does not necessarily coincide with periods of maximum water usage by any of these system components. The measurement technique that we have envisioned is based on a combination of Bowen ratio techniques for total evapotranspiration and a soil heat balance technique for evaporation. The regular Bowen ratio technique would allow determination of all components of evapotranspiration in the vineyard in a single lumped term. The micro Bowen ratio technique (~ 6 cm tall), installed below the grape canopy, would allow determination of evapotranspiration corresponding to the interrow treatment (e.g., grass or bare). Finally, the soil heat balance technique would allow determination of the soil component of evapotranspiration (i.e. evaporation). By difference between these three estimates, we could determine grape transpiration, interrow transpiration, and evaporation. Utilizing this combination technique, we can characterize the daily, seasonal, and total water use from each vineyard system component.

Last Modified: 7/12/2014
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