1a.Objectives (from AD-416):
1. Develop sustainable water management strategies for wine, table, raisin, and juice grape production using limited water supplies.
2. Develop sustainable water and soil management strategies for minimizing the impacts of drought and salinity on the root zone environment, grape yield and quality.
3. Establish rootstock recommendations based on drought resistance and salinity tolerance.
4. Quantify the effects of various water management strategies on fruit and product composition, and sensory qualities.
5. Quantify the economic impacts of drought and salinity on grape production under different biophysical soil and water characteristics and alternative management strategies.
6. Disseminate study findings via web based education and farmer outreach.
1b.Approach (from AD-416):
This research will be conducted using both laboratory and field research sites. The field research will be conducted in the Central Valley and Paso Robles, CA, and in Washington State. Laboratory studies will be conducted at UC Davis and the Salinity Laboratory in Riverside, CA, as well as a Washington State University in Pullman, WA. Specialty Crops Research Initiative.
This project supports objective 1 of the parent project. This is a multi-state and multi-institute research project that is evaluating sustainable water management practices for table, wine, raisin and juice grapes being grown in California and Washington State. The water management strategies are evaluating the effect of deficit irrigation on fruit and wine quality as well as yield. The economic impact is being evaluated by an economist at the University of California Riverside. The impact of irrigation management on soil salinity is being evaluated by ARS scientists at the United State Salinity Laboratory. Rootstocks are being evaluated for both salt and drought tolerance by ARS and UC Davis scientists. The details of the research by scientists from UC Davis and Washington State University are given in research reports for the individual projects covering the economics (5302-13000-011-10G), technology transfer (5302-13000-011-09G), rootstocks (5302-13000-011-11G) and water management strategies for juice and wine grapes (5302-13000-010-16G). Field trials have been established on four locations in California to quantify the impact of deficit irrigation on early and late season table grapes, raisin grapes and wine grapes. There are a total of 3 irrigation treatments with 4 replications on each trial in California. The irrigation treatments are based on grape physiology and grower practice. The control treatment is the current grower practice. The second treatment is 80% of the grower practice throughout the season and the third treatment varies the depth of irrigation in relation to the grower practice before and after verasion. Depth of applied water is 80% of grower practice up to verasion and 50% after verasion (ripening) up to harvest. This is the second year of operation of the study. There was a significant reduction in applied irrigation water on the third irrigation treatment during the first season on the early season table grapes. The third treatment resulted in lower yields and poorer quality grapes in the early season table grapes in the second year harvest. There are no data yet for the late season table grapes in the second year. Wine analyses for the first year are not completed. A capacitance probe system for measuring soil water remotely has been installed in each treatment of the California trials. This system measures the change in soil water content and sends the data over a wireless network. These data can be accessed in real time to monitor the crop water use and irrigation.