Water Conservation in Wine Grape Production

An infrared thermometer (IRT) was used to schedule irrigation in five vineyards. Chardonnay vines in Madera and Santa Maria, CA; Chenin Blanc vines in Madera, CA; and Cabernet Sauvignon vines in Madera and Paso Robles, CA were used in this project. Water was applied to drip irrigated vines only when IRT measurements indicated a certain level of water stress. If vines were below that stress level, water was withheld until stress increased to the selected level. Treatments were imposed from veraison to harvest at the Madera and Santa Maria locations; and from berry set to harvest at the Paso Robles location. Water use for irrigation was reduced by up to 3 0%in this study. The amount of water saved depended on environmental conditions and the irrigation scheduling practices of the grower-cooperator. Irrigation scheduling treatments had no significant effect on vine yield or dormant pruning weight. Fruit composition displayed only a small response to the treatment. In general, %soluble solids of fruit were increased by increasing water stress. The effect of treatment on titratable acidity and pH was not consistent. These results are preliminary and several more years of data collection are required before equilibrium results can be obtained. Commercially available microsprayers were tested in the Center for Irrigation Technology Sprinkler Testing Laboratory on the CSU, Fresno campus. All microsprayers tested were not suitable for targeted frost protection of vines. Prototype microsprayers from two manufacturers were also evaluated. The Wade Manufacturing Pulsator was identified as being capable of providing adequate targeted frost protection with a flow rate of approximately 11 gpm/acre. Thus, the commercial application of this technology would substantially reduce water use for frost protection. Additional testing is needed to evaluate the Pulsator microsprayer under field conditions using differential application rates.