(Wines&Vines) - Droughts in California and Texas; lower levels in subsurface aquifers across the west; water-quality issues in other places: all have implications for agriculture—and specifically for growing grapes. Consequently, water-use efficiency was a timely topic for the daylong seminar at the 65th annual conference of the American Society for Enology and Viticulture in Austin. On June 24, approximately 125 people attended sessions covering a wide range of topics, from the role of xylem cell structure and function in water relations to using current technology for scheduling the most efficient use of irrigation.

Wine grapes require less water to mature than some other crops, and often rainfall can provide much of the required water. However, when water of marginal quality is used for irrigation, the level of soil salinity can increase, according to Donald L. Suarez, laboratory director at the USDA Agriculture Research Service Salinity Lab in Riverside, Calif. As a result of the changes in salinity, it may be necessary to alter water-management practices, and possibly include leaching to control the level of salinity. 

Suarez presented a study designed to evaluate the effectiveness of leaching to control root-zone salinity by drip or sprinkler irrigation at three sites. He found that there was a “winter irrigation window” when the plants were dormant and the soil was wet, and leaching at that time had a “major impact on spring salinity levels, even in years of average to low rainfall.” Drip irrigation was more effective on heavier soils and sprinklers on sandy soils.