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GRAPEGROWING Actual Vineyard Evapotranspiration Gallons per vine 8 6 4 2 0 Date MayJuly SepNov Figure 1: Actual vineyard evapotranspiration from a Wente Vineyards Cabernet Sauvignon block. The data from the surface-renewal system tells grapegrowers how much water evaporated from the vineyard since the last irrigation, helping them decide how much to replace with the next irrigation. Promote your wines to leading Zinfandel enthusiasts and extend your winery's relationship in the market. Join Us! We are champions of Zinfandel— America's Heritage Wine Become part of our proud legacy zinfandel.org • 530-274-4900 Technology validation Zinfandel Advocates & Producers is a 501(c)(3) non-profit organization. ZAP is dedicated to advancing public knowledge of and appreciation for American Zinfandel and its unique place in our culture and history. At the UC Kearney Agricultural Center vineyard in Parlier, Calif., surface renewal was validated against two research techniques: lysimetry and eddy covariance in 62 p r acti c al w i ne ry & v i ne yard FE BRUARY 20 14 2012 and 2013. Figure 2 shows a sample of data from the experiment in 2013. In two commercial Napa Valley vineyards (each 2.5 acres of Cabernet Sauvignon) in 2012, surface renewal was validated against eddy covariance. The Actual Evapotranspiration 15 Gallons per vine per day You know how good your Zinfandel is... lysimeter or eddy covariance system. In the field of evaporation and irrigation science, lysimetry and eddy covariance are the "gold standards" for measuring water use, and they often are used to calibrate other technologies. The research group developed a method to eliminate the calibration requirement. The method was validated by applying it to 20 years of surface renewal studies reported in scientific literature related to various crops including wine grape and table grape vineyards. It has also been validated with new data sets from 2012 and 2013 in California vineyards. Commercial measurements of actual evapotranspiration have not been available previously because expensive instruments and equipment were required to characterize the turbulent wind motions. The expense of those methods, such as lysimetry and eddy covariance, limited actual evapotranspiration measurements to the research sphere and well out of reach of practical agriculture. Surface-renewal equipment is relatively inexpensive, making actual evapotranspiration measurements commercially viable for grapegrowers. UC Davis owns the intellectual property, and Tule Technologies has the exclusive license to commercialize the technology. Tule Technologies charges an annual subscription fee for providing actual vineyard ET data to growers. 10 5 0 Lysimeter Surface Renewal Date 7/01 7/03 7/05 7/07 7/09 7/11 7/13 Figure 2: Sample surface renewal validation data from a vineyard at the University of California Kearney Agricultural Center in 2013. The data are daily actual vineyard evapotranspiration (ET) values (gallons per vine per day) measured using surface renewal and a weighing lysimeter. The lysimeter measures evapotranspiration by examining the weight loss that occurs as the plants and soil in a large buried pot lose water to the atmosphere. Note that the lysimeter measures the ET from two vines, while surface renewal measures the ET from many vines over a broad area.