Proceedings of a workshop held at the Waite Campus, Adelaide University, 3 September 2002, to review and scope needs on efficient water use in viticulture.

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Increasing vineyard water use efficiency is a major goal of the wine industry. Strategic water management to increase grape quality is similarly an industry priority. Precise knowledge of vine and cover crop water requirements, soil evaporation and 'leakiness' are fundamental to achieving water use efficiency. Traditional approaches for estimating vineyard water requirements are based on use of pan evaporation data and crop coefficients. Soil moisture monitoring, using anything from visual assessment to sophisticated soil moisture sensors, has also been widely adopted as an irrigation scheduling tool over the last decade. Such approaches generally arrive at estimates of evapotranspiration (ET), which is a composite of actual vine and cover crop transpiration and soil evaporation. The advent of sap flow sensing technologies that enable the direct measurement of vine transpiration has suggested vine transpiration values in a range equivalent to 0.5 to 2.0 megalitres per hectare per season (depending on canopy size etc) which is lower than expected relative to traditional methods of measurement. Furthermore we know that deficit irrigation technologies such as PRD and RDI have the capacity to significantly modify vine water use through physiological changes. The impact of this on vine water use needs to be considered in developing meaningful crop factors.

The key questions addressed at the workshop were as follows:

• The accuracy of current estimates of vine transpiration, cover crop transpiration and soil evaporation;
• Knowledge gaps;
• Research required to fill the gaps;
• Prioritisation of the research needs;
• Structuring the research, regionally and nationally;