Water Management for North Carolina Wine Grape Production.

Wine grape (V. vinifera) production is a rapidly growing industry in North Carolina, primarily located in the Mountain and Piedmont regions of the State.  Management practices for these grapes have largely been adapted from more established grape growing regions. Since temperature and water regimes strongly influence wine grape yield and composition, water management practices from other regions may need to be adjusted for the unique climate and soils of North Carolina.  Grapes grown in North Carolina typically depend on natural rainfall; irrigation is used only occasionally for vine establishment or to supplement rainfall. If there is a rainfall deficit, which can be common during the middle of the growing season, production suffers due to reduced growth.  If rainfall amounts are in excess of evapotranspiration, which is common in the early and late growing season, grape quality can suffer and disease pressure increases.  A water management tool is needed to assist growers in irrigation management decisions.  Development of this tool was initiated by instrumenting two vineyards in the Yadkin Valley.  Soil matric potential and weather parameter data are collected continuously.  Soil water potential data are used to determine soil water status, and weather parameter data are used to compute FAO Penman-Monteith reference evapotranspiration.  Profile volumetric soil water content and midday stem water potential were measured periodically during expected peak water use periods at each vineyard during the growing season.  Preliminary results from the first year of the project will be presented.