THE POTENTIAL FOR USING UNDER-VINE COVER CROPS AS AN ALTERNATIVE TO HERBICIDES IN COOL CLIMATE VINEYARDS EL POTENCIAL DE UTILIZACIÓN DE COBERTURAS VEGETALES DEBAJO DE LA PLANTA COMO UNA ALTERNATIVA A LOS HERBICIDAS EN LOS VIÑEDOS DE CLIMAS FRÍOS

VANDEN HEUVEL, Justine1; JORDAN, Lindsay2; KARL, Adam3; CHOU, Ming-Yi3; CENTINARI, Michela4 1 Associate Professor, School of Integrative Plant Science, Cornell University, Ithaca and Geneva, NY USA Former MS student, School of Integrative Plant Science, Cornell University, Ithaca and Geneva, NY USA. Current position: University of California Cooperative Extension, Madera, CA USA 3 PhD student, School of Integrative Plant Science, Cornell University, Ithaca and Geneva, NY USA 4 Former Postdoc, School of Integrative Plant Science, Cornell University, Ithaca and Geneva, NY USA. Current position: Assistant Professor, The Pennsylvania State University, University Park, PA USA 2 *Corresponding author: jev32@cornell.edu

Abstract: Six multi-year, replicated field experiments were conducted to investigate the potential of under-vine cover crops to replace herbicide use in vigorous vinifera vineyards in the Finger Lakes region of New York State. Under-vine cover crops of buckwheat and annual rye grass resulted in few consistent differences in vegetative growth measures, yield, petiole nutrient concentrations at veraison, or midday stem water potentials. Chicory, white clover, and native vegetation (NV) (i.e. weeds) as under-vine cover crops reduced pruning weight, vine yield, and petiole N concentration. Soil microbial respiration was greater in NV and white clover cover crop treatments compared to glyphosate plots, while dissolved organic carbon leachate concentrations were greater in glyphosate plots compared to cover crops. Less nitrogen leached from NV plots compared to glyphosate and white clover plots. Compared to glyphosate-maintained bare soil, the soil microbiome of NV plots was greater in richness and led to differences in relative abundance among the shared fungal and bacterial genera. Soil health (organic matter content, aggregate stability) was also improved. Riesling wines from vines with under-vine cover crops had altered aromatic properties but the aromatic and gustatory properties of Cabernet franc were not affected. These studies demonstrate the potential of under-vine cover crops to reduce vine size, improve soil health and decrease the leaching of nutrients in comparison to herbicide use, however the impacts of these treatments on aromatic properties of the resulting wines requires further investigation.

Keywords: herbicide, leaching, soil health, cover crop, wine