Cool Climate Oenology and Viticulture Institute, Brock University, St. Catharines, ON, Canada L2S 3A1
Journal of Applied Horticulture, 2014, volume 16, issue 2, pages 87-102.
Abstract: The possible influence of vine water status on grapevine yield components was studied in ten Vitis vinifera L. Cabernet franc vineyards in the Niagara Peninsula, Ontario from 2005-2007 using geomatic techniques. Soil texture, soil chemical composition, soil moisture and leaf water potential (?; vine water status), were determined on ? 80 sentinel vines in each vineyard. Water status zones were identified in GIS-generated maps using leaf ? and soil moisture measurements. Areas of low soil moisture and low vine water status were negatively correlated linearly and spatially with vine size, yield, and berry weight. The frequency of relationships between variables was vineyard- and vintage-dependent. Spatial variability in soil moisture was temporally-stable in all vineyards across the three vintages (8-10 sites; 2005-06, 2006-07, 2005-07), while vine size (6-7 sites), berry weight (2-7 sites) and yield (2-5 sites) were likewise moderately-stable, but leaf ? was not (two sites). These data suggest that low soil moisture and low vine water status zones in vineyards are related to corresponding areas of low yield and vine size. These data further suggest that precision viticulture techniques may be utilized in this region to delineate yield-based or vine vigor-based vineyard sub-zones that relate to differing quality levels.