Saving water while increasing yield and quality? This is possible.
Thanks to a grant received from the Water Metropolitan District of Southern California, we set up an experiment last year with the help of 6 independent wineries, under contrasted California climates. The goal of the experiment was to evaluate how much irrigation water could be saved and how was affecting yield and maturation compared to traditional irrigation practices.
Less than 5 irrigations across all location during a drought year
Because vine water use was continuously available online, sap flow-based irrigation resulted in less than 5 irrigations across all locations, versus 6 to 30 times in the traditional treatment. As a result, water savings using sap flow sensors were dramatic with on average 65% less water applied. Contrary to common thinking, water savings did not affect yield negatively and no difference was observed between treatments (NB: yield ranged from 2 to 4 tons/acres at each location). In fact, dehydration was sometimes observed when more water was applied early season. Thus, yield was even lower under the traditional treatment in 3 situations. There was also no difference in sugar accumulation rates between treatments. Brix at harvest was between 23 and 27 degrees; fruit quality was preferred in the sap flow treatment, which is a direct benefit from imposing moderate water deficit before veraison.
Thibaut holds a Ph.D. in viticulture from the French National Institute of Agronomy at Montpellier, France. His research focused on vine water status variations under dry climates and their consequences on berry ripening. Thibaut also serves as a scientific consultant for various high end vineyards in Napa Valley. Prior to his Ph.D., Thibaut worked as a winemaker for various companies throughout the world (Chile, California, France and Australia). In 2001, he was hired by Robert Mondavi winery as a research viticulturist: his projects focused predominantly on mapping the vineyard variability, analyzing vineyard practices and vine water deficit impact on fruit composition. Thibaut earned a Masters degree in Viticulture and Enology in 1997 and a Masters degree in Winemaking in 1998 from SUPAGRO, one of the top agronomy school in France.
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