Patricia A. Skinkis,* Mathew R. Lange, Andy Gallagher, and R. Paul Schreiner
*Oregon State University, 4017 Ag & Life Science Bldg, 2750 SW Campus Way, Corvallis, OR, 97331 (patricia.skinkis@oregonstate.edu)

There is increasing concern about vineyard water management given climate vari­ability and recent widespread drought in the American West. Traditionally, growers in Oregon’s Willamette Valley could produce winegrapes without irrigation due to sufficient annual rainfall and soils with high water-holding capacity. Since the major­ity of vineyards in this region are dry-farmed, understanding soil water availability and vine response is imperative when making early season management decisions, such as vineyard floor management practices. A multi-year observational study was conducted to understand seasonal vine growth response to soil water content, with a focus on summer, when rainfall is minimal. The research was conducted in a Pinot noir vineyard with soils from sedimentary, volcanic, and glacial flood parent mate­rials. Vineyard blocks were uniform in rootstock, age, vine spacing, training system, and management. Soil moisture was monitored continuously throughout the year undervine and between rows at 46 cm and 91 cm soil depths at two monitoring locations within each soil type. Soil type primarily impacted vine vegetative growth and productivity, with vines in the glacial soil having the greatest dormant prun­ing weights, vine leaf area, and tissue nitrogen status. This soil type also produced greater yields and cluster weights. Vines in the other two soil types had greater vine water stress, as measured with leaf water potential, smaller canopy sizes, and more advanced ripeness at harvest. Interestingly, soil moisture undervine was reduced in the glacial soils, yet the canopies grew larger, suggesting the soil profile was deeper, thereby facilitating deeper vine rooting, or that the vines used up more water in the upper soil profile due to greater water demand. This project provides important in­formation on vine response to soil moisture dynamics that may assist future vineyard management decision-making

Funding Support: Oregon Wine Board and Erath Family Foundation