Project Number: 5358-21000-034-22
Project Type: Reimbursable

Start Date: Oct 01, 2006
End Date: Jul 14, 2008

Objective:
Build and install "bridge" units in a well-watered juice grape vineyard trained on a single-curtain trellis; compare bridge-load cell system with open-ended load cell measurements; collect continuous data to monitor the crop and estimate yield; and collect intensive supplemental data on vegetative and reproductive growth. Build and install "bridge" units in a deficit-irrigated wine grape vineyard on a modified sprawl trellis; compare bridge-load cell system with openended load cell measurements; collect continuous data to monitor the crop and estimate yield; and 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 bridge-load cell system; and compare processor's 10-site yield estimate with that derived from the tension measurements.

Approach:
A set of bridges will be installed in a research block of 20-year old, well-watered juice grapes trained to a single curtain on a cordon wire at six feet above the soil. Initial wire tensions will be set before bud break. Each bridge-load cell unit will be paired with an open-ended load cell installation. The load cell installations will be monitored continuously from bud break in 2005 through dormant pruning in 2006. Intensive periodic measurements of vegetation will be recorded to add to our growing database that will supply information for models of vegetative mass in this system. Another set of bridge-load cell units will be installed in a research vineyard of six-year old, deficit irrigated wine grapes trained to a modified sprawl with a single cordon wire at 42" and two foliage catch wires at 60". Portions of the existing sprawl trellis either will be left intact or modified to reduce the number of load-bearing elements (e.g., some vine stakes removed). All fruit will be harvested by hand. Intensive periodic measurements of vegetative growth will be recorded from fruit set until harvest. The load cell installations will be monitored continuously from bud break through dormant pruning in 2006. Documents Reimbursable with UC Davis. Log #32745.