Vine-row Groundcover Management Affects Pruning and Cluster Weights, Petiole C and N Content, and N Leachate in a New York Vineyard

New York vineyards are often situated on fertile soils where excessive vine growth causes problems with high vigor and undesirable “green” flavors in red wine-grapes. We are comparing the effects of four vine-row groundcover management systems (GMS) on vine nutrient status, vine growth and yields, soil conditions, and nutrient leaching in a Finger Lakes ‘Cabernet Franc’ vineyard. Four GMS treatments were maintained in 1-m-wide strips beneath the vine rows: 1) native vegetation; 2) glyphosate herbicide; 3) white clover (Trifolium repens) seeded in May each year; and 4) mechanical cultivation. After two years of treatments, fruit yields, dormant pruning weights, cluster counts, and cluster weights were greater in glyphosate plots than in other treatments. Petiole C and N content were greatest in white clover plots, and soil N and K availability were greater in the glyphosate and white clover plots.  Subsoil N leaching was greater beneath white clover plots, while dissolved organic carbon leaching was greater in cultivated and glyphosate treated plots. Volumetric soil water content usually ranked glyphosate > cultivated > native vegetation > white clover during the growing season, but vine water potential was not closely correlated with soil water content even during a prolonged drought during 2012.