Monitoring helps winegrape growers save water
By JULIA HOLLISTER
For the Capital Press
Mark Greenspan is teaching vineyard managers in California to save as much as half the water they normally use on irrigation.
“I did my graduate work in water on grapevines with irrigation and water management,” Greenspan, owner of Advanced Viticulture in Windsor, Calif., said. “I worked for Gallo doing research projects with mostly water management, then started consulting in 2005.”
He worked with the Sonoma County Water Agency and the Sonoma County Winegrape Commission recruited him to work on an outreach water project.
“The idea was to demonstrate what we do working with growers at Constellation Vineyard and manager Tom Gore,” he said. “I selected two very different two blocks in Alexander Valley — one was in a deep, rich, heavy clay soil and another with a rocky soil.”
Greenspan wanted to contrast the two locations and manage them differently. He picked them because both had similar root stock but were irrigated differently.
He put 4-foot-long probes in the soil that recorded how much moisture was in the soil and whether the remaining water was taken up by the plant.
“The probes also recorded how deep irrigation goes because we didn’t want to irrigate past the rooting depth,” he said. “The instruments allowed us to monitor that and to determine how quickly the water has been taken up by the plant.”
The soil was measured continually and the plants monitored weekly. The aim was to provide just enough moisture in the soil to allow plant growth.
“The main thing is for me to work with the growers to indicate to them that with this they don’t have to irrigate on a certain schedule,” Greenspan said. “I wanted to allay the fear that grew from the belief that they are running out of water.”
The growers were surprised by the result. During 2012 and last year, they didn’t start irrigating until late summer. The conservation project saved over 50 percent of the water the growers normally used.
The study was funded through a USDA grant from the Sustainable Agriculture Research and Education.
“My goal was to teach and train the growers and vineyard managers how to use these tools,” he said. “Twenty-five percent of vineyards in the county are now using these tools.”
Brad Sherwood, spokesman for the Sonoma County Water Agency, recognized the importance of Greenspan’s efforts.
“Mark’s work is instrumental in creating awareness and educating local grape growers on water conservation and the best management practices,” he said “This is especially important now, given the drought we are facing because every drop of water does matter.
“He has been able to reach out to the growing community and we think that not only helps build relationships but puts words into action.”