RT Journal Article SR Electronic T1 Applications of Geospatial Technologies to Understand Terroir Effects in an Ontario Riesling Vineyard JF American Journal of Enology and Viticulture JO Am J Enol Vitic. FD American Society for Enology and Viticulture SP ajev.2016.16083 DO 10.5344/ajev.2016.16083 A1 Matthieu Marciniak A1 Andrew Reynolds A1 Ralph Brown A1 Marilyne Jollineau YR 2017 UL http://www.ajevonline.org/content/early/2017/01/05/ajev.2016.16083.abstract AB The objective of this study was to determine whether yield components and grape berry composition variables would be related to and dependent upon soil texture and composition, vine water status [i.e. leaf water potential (ψ)] and vine size, and to assess whether spatial patterns of leaf ψ, vine size, and other field variables would be temporally stable. Data were collected in a 10-ha Riesling vineyard at Thirty Bench Winemakers, Beamsville, ON. The vineyard was delineated using global positioning systems and 519 vines were geo-referenced in six sub-blocks. Soil water content (SWC; all sentinel vines) and leaf ψ data (a subset of 134 sentinel vines) were measured bi-weekly from 2006—2009, inclusive. Soil texture and composition data were also collected on the 134-vine subset. Yield components (yield, clusters per vine) and berry samples were collected from each sentinel vine, with an additional berry sample for monoterpene determination from the subset. Vine size was determined by weight of cane prunings. Berry samples were analyzed for Brix, pH, and titratable acidity (TA) and the additional berry samples for free and potential monoterpenes. All variables were mapped using geographic information systems, which permitted verification of temporal stability as well as correlative and spatial relationships. SWC and leaf ψ were temporally stable throughout the vineyard despite extremely different weather conditions. There was an increase in Brix and pH and a decrease in TA (≈ enhanced grape maturity) with decreases in SWC, leaf ψ, and vine size. In the case of very high SWC, decreases in leaf ψ, vine size, and fruit maturity were observed. Sub-blocks with highest sand and soil organic matter tended to have higher vine sizes and berry monoterpenes.