2007 Annual Report 1a.Objectives (from AD-416) In a well-watered juice grape vineyard trained on a single-curtain trellis, compare the finite-length load cell system with open-ended load cell measurements; collect continuous data to monitor the crop and estimate yield; collect intensive supplemental data on vegetative and reproductive growth. In a deficit-irrigated wine grape vineyard on a modified sprawl trellis, compare the finite-length load cell system with open-ended load cell measurements; collect continuous data to monitor the crop and estimate yield; collect intensive supplemental data on vegetative and reproductive growth. In ten commercial juice grape vineyards, couple a local processor's sentinel vine system for yield estimation via hand sampling with measurements of trellis wire tension using the finite-length load cell system; compare processor's 10-site yield estimate with that derived from the tension measurements. Post data from the research vineyard to the WSU viticulture website with the assistance of Dr. Mercy Olmstead, WSU-Extension Viticulturist. 1b.Approach (from AD-416) We developed a novel approach to estimating yield in grapevines by continuously measuring the tension in the horizontal (cordon) support wire of a single-curtain trellis. Load cells and temperature sensors installed in-line with the cordon wire are connected to an automated data acquisition system, a major departure from the industry's standard method of collecting fruit samples by hand two or three times per growing season. Each row in the experimental vineyard is calibrated at the beginning of the season to determine the change in tension in that row in response to an increase in known mass (weight) hung on the cordon wire. The effects of temperature on wire tension are removed by post-processing with a regression-based empirical protocol, which corrects the raw data to a standard temperature. Because data are averaged over 15 min, wind gusts have little detectable effect on the tension measurement. A smoothing algorithm removes remaining transient disturbances in the data without masking significant events like crop thinning or harvest. There appears to be a linear relationship between wire tension and fruit mass (yield) that varies among rows, but not within a row, during a single season. Documents Trust with Washington Wine Grape Industry Foundation. Log 28976. 3.Progress Report This report serves to document research conducted under a trust agreement between ARS and Washington Wine Grape Industry Foundation. Additional details of research can be found in the report for the parent project 5358-21000-034-00D, Production Systems to Promote Yield and Quality of Grapes in the Pacific Northwest. Dr. Tarara and collaborators conducted the following research towards the agreements objectives: During 2006, progress was made in three main areas. First, in a research vineyard, continuous estimates of yield were made with an empirical model that used the tension record and final yield from preceding years. This approach also was pursued for a "bridge" system paired with an "open" system within the same row. The "open" systems significantly underestimated actual yield while the "bridge" estimate came within ~10%. The predictions derived from this simple approach became fairly stable in early July, well before the onset of ripening (mid-August). The second area of progress was the second complete season of tension measurement using paired "bridge" and "open" systems in 10 commercial juice grape vineyards. The 2005 data were used to test yield prediction during 2006. The tension records from these vineyards demonstrated the sensitivity of the load cells to overhead irrigation. Other management practices like mechanical thinning also were detected in the wire tension. There are some transient fluctuations in the tensions for which we have no hypothesis to date. The third area that we pursued was to modify the "bridge" system for wine grapes in a research vineyard with a single cordon wire and two foliage wires. Five pairs of "bridge" and "open" load cells were installed and tension measured continuously from before budbreak through harvest. During 2007, the 52 trellis tension monitors in our 13 sites will continue to operate. The continuous stream of data will be used to track vine growth during the season and to predict yield. With the additional year added to the database, yield predictions should become more robust. Collaborating with WSU Extension, we posted graphic depictions of the tension records to the web (http://www.fruit.wsu.edu/Grapeweb/cropload.htm) weekly. During 2006, this included estimation of yields at each load cell installation. USDA-ARS holds a U.S. patent (no. 6,854,337) on this technology. A major U.S. winery and a major Australian winery are working with a small number of trellis tension monitors on an experimental basis, beginning in 2006 (Australia) and 2007 (U.S.). Widespread commercial application on farms requires a private sector engineering-manufacturing partner to commercialize the load cell and datalogging equipment, and to write robust software for data processing with a suitable graphical user interface. ADODR Statement: The ADODR met with the cooperating PI and project personnel at meetings during the year and discussed results through phone calls, e-mail, and in person.