Gillian Hawkins, Pete Jacoby,* and Xiaochi Ma
*Washington State University, 1135 SW Marcel St, Pullman, WA 99163 (jacoby@wsu.edu)

Water availability is a growing concern as the wine industry continues to expand. Washington irrigation sources are dwindling, but with efficient, water conserving irrigation, the amount of water used in vineyards can be reduced while producing high-quality winegrapes. Cabernet Sauvignon grape vines at Kiona Vineyards in the Red Mountain AVA were subjected to direct root zone (DRZ) irrigation during the 2017 growing season. Water was delivered directly to the lower root zone of each vine at 0 and 2-foot depths through one-inch diameter PVC piping at 80, 60, and 40% of commercial irrigation. DRZ irrigation remained at a commercial rate for the beginning of the growing season until fruit set, when water application rates were reduced to specified percentages for the remainder of the growing season. With DRZ irrigation, no significant differences were observed in pH, tannin concentration, anthocyanin concentration, or Brix. Berry diameter was reduced as water application was reduced. Further experimentation with these water rates and irrigation depth will be done to understand the long-term effects of water stress on the productivity of the vines.

Funding Support: Washington Grape and Wine Research Program, Northwest Center for Small Fruit Research, Washington State Concord Grape Research Council, WSDA, and Western Sustainable Agriculture Research and Education