By Matt Gura '13
Master's student Lindsay Jordan knew that she wanted to approach viticulture research with a core focus on sustainability. Growing up in California, she saw prime farming land used for grapes, almonds and other crops become abandoned after it became too saline or too crusted from decades of irrigation.
"This was the first, but certainly not the last time, that I encountered the effect of large scale 'conventional' agriculture on the environment," said Jordan. "With increasing population and food demand, we have to treat what farmable land we have as a valuable resource."
Jordan earned a B.S. in Enology and Viticulture from U.C. Davis, before setting her sights on east coast viticulture, where many of the challenges to sustainability can be traced back to heavy rainfall and high humidity. Heavy rainfall coupled with soil fertility can tip vines out of balance and create a weedy carpet under the canopy. Most growers maintain an herbicide strip beneath the vines or cultivate to reduce weeds. However, the sustainability of these practices is being called into question. The objective of Jordan's work was to determine if under-vine cover crops could be a sustainable alternative to herbicide use in Finger Lakes vineyards.
"The cost of maintaining an herbicide strip beneath vines is high," says Justine Vanden Heuvel, associate professor of horticulture at Cornell University and Lindsay's graduate advisor. "It's been estimated to be at least $230 per acre in the Finger Lakes. However we think the cost of planting and maintaining an annual cover crop could be as low as $75 per acre."
For three growing seasons, Jordan conducted experiments with under-vine cover crops in Riesling blocks at Wagner Vineyards in Lodi, NY. Annual rye grass, flowering buckwheat, and natural vegetation were pitted against an herbicide control, and their impact on yield, fruit chemistry, and wine aroma was assessed.
According to Jordan, none of the under-vine cover crops had significant impacts on soluble solids, pH, yeast assimilable nitrogen, or titratable acidity. Yield and yield components were not affected either. The only variable that really was impacted was the aromatic properties of the resulting wines.
"We had a sensory panel determine whether the wines from the cover crop treatments differed from the herbicide treatment," explained Jordan. "In fact, they did. The cover crops changed the aroma of the wines."
Her work garnered the top spot in the student paper competition at the 2013 American Society of Enology and Viticulture- Eastern Section Conference. The question of why and how the aromatic properties of the wines were impacted is something Lindsay hopes to answer while she pursues a Ph.D. in viticulture with Vanden Heuvel.
"Lindsay was the perfect student to put on this project due to her strong interest in improving the sustainability of winegrape production," said Vanden Heuvel. "We're still a ways off from making specific recommendations, but if we can replace herbicide use in vineyards with under-vine cover crops, the economic and environmental sustainability of winegrape production would be greatly increased."
Matt Gura '13 is a graduate of the Viticulture and Enology and program now serving as hops manager for Ceres Hop and Grains LLC in South Bend, IN.