Measuring the Influence of An Inter-Row Fescue Crop On the Below-Canopy Humidity In a North Carolina Vineyard.

Growing European grape varieties for wine making is an expanding industry in the southeastern U.S. However, the southeastern climate differs from climates where European grapes are traditionally grown. The southeast has high precipitation and soils with poor internal drainage, which lead to high humidity.  High humidity, in turn, creates ideal conditions for fungal diseases. Without adaptations to management practices to reduce canopy humidity, fungal diseases will continue to limit the local wine grape industry. Altering inter-row management practices may offer a solution. We hypothesize that inter-row crops, typically fescue, serve as a pump extracting water from the soil, which increases below canopy humidity. The following objectives seek to test this hypothesis; 1) estimate and compare surface water vapor flux under (i.) bare soil conditions and (ii.) fescue cover crop conditions in the inter-row and in the vine row and 2) characterize and compare the humidity profile from the ground surface to the upper canopy for bare soil conditions and fescue cover crop conditions. Research is being conducted at a commercial vineyard in the Yadkin Valley Appellation. Measurements of below canopy water vapor flux are collected with a micro-Bowen ratio system. Microlysimeters and profile water content measurements are being used to monitor soil water dynamics within the vineyard. Below-canopy humidity is monitored at several heights. Together, these data will be used to compare the inter-row water balance between treatments. Preliminary results show the vapor flux is greater in the grass inter-row compared to the bare soil inter-row. The measured vapor flux is being evaluated to determine its influence on the below-canopy humidity. Experiments are on-going.