What is in this article?:
- Timely advice saved North Carolina vineyard
- Close to panic
• Cathy Powell’s journey down this road began six years ago when she tried to save an especially cherished grape vine on her family property. One thing led to another, and now she has acres of grapes — red and white muscadines as well as the hybrid Cynthiana/Norton, grown by Thomas Jefferson and known as the “cabernet of the Ozarks.”
Close to panic
“I about panicked when I saw the cupped, burnt foliage,” she said. “After you put that much work in a vineyard, . . . seeing that kind of damage . . . you about have a stroke.”
Powell summoned Cooperative Extension agent Colleen Church to help troubleshoot the problem. Church took photos and collected plant tissue samples for nutrient analysis. When tests confirmed that boron was present in toxic amounts, Church suggested Powell contact regional agronomist J. Ben Knox with the North Carolina Department of Agriculture and Consumer Services. She knew that he was more familiar with grapes and that crop nutrition was his particular area of expertise.
When Knox visited, saw the plants and looked at the report results, he was astounded by the high levels of boron.
“Lowering levels of boron is possible,” Knox said. “I’d just never seen a situation where they needed to be lowered so much.”
After consulting with fellow agronomist Bill Yarborough, Knox suggested that Powell water the vineyard heavily to move as much boron as possible out of the root zone. Then he advised her to apply calcium through the drip irrigation system to raise the soil pH. As soil pH increases, boron becomes chemically tied up, reducing its availability to plants.
Knox and Powell continued to monitor the problem by collecting and submitting plant tissue regularly. It took several months to see improvement, but by the next year, the plants had begun to recover. They had slightly less foliage and produced fewer grapes than the ones that had not received extra boron, but they were alive and regaining vigor.
“Dealing with this problem helped the Powells identify and address other nutrient issues,” Knox said. “Using tissue reports, I explained the importance of potassium in particular. After increasing this nutrient, Powell saw a noticeable increase in the size of the grapes."
Powell has continued to use agronomic testing services and solicit Knox’s input. She submits soil and tissue samples when she notices vines ripening unevenly and then applies spot treatments of lime and fertilizer based on report recommendations. Ripening has become much more uniform.
It takes several years for grape vines to become established, and Powell’s vines are just now maturing to the point where they can be harvested. They produced three tons of fruit this year. The Cynthiana/Norton variety is going to the Wolfe and Silk Hope wineries. Powell is excited about this arrangement since Silk Hope Winery is a recent Silver Medal winner in the 2010 Mid-Atlantic Southeast Wine Competition for its Haw River Norton 2008 vintage.
Powell feels like she has reached an important milestone and is grateful for the assistance she received in getting there. She looks forward to getting established and reaching the point where she can make her own wine.
“It is so important to have an adviser to rely on because there’re always going to be little things that come up,” Powell said. “I think Ben’s a knight in shining armor. Without his advice and the agronomic testing services, I probably would have lost my grapes.”
The NCDA&CS Agronomic Division has 13 regional agronomists who can make on-site visits, evaluate suspected nutrient problems and give advice on collecting and submitting agronomic samples, understanding test results, liming, fertilization, composting, irrigation and nematode management. To contact the agronomist assigned to your area, visit http://www.ncagr.gov/agronomi/rahome.htm.