Applications of Geospatial Technologies to Understand Terroir Effects in an Ontario Riesling Vineyard

Abstract

The objective of this study was to determine whether yield components and grape berry composition variables were related to and dependent upon soil texture and composition, vine water status (leaf water potential, Ψ), and vine size and to assess whether spatial patterns of leaf Ψ, vine size, and other field variables were temporally stable. Data were collected in a 10-ha Riesling vineyard at Thirty Bench Winemakers in Beamsville, ON. The vineyard was delineated using global positioning systems and 519 vines in six sub-blocks were geo-referenced. Soil water content (SWC; all sentinel vines) and leaf Ψ data (a subset of 134 sentinel vines) were measured bi-weekly from 2006 to 2009. Soil texture and composition data were also collected for 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 and correlative and spatial relationships. SWC and leaf Ψ were temporally stable throughout the vineyard despite extremely different weather conditions. There was increased Brix and pH and decreased TA (enhanced grape maturity) with decreases in SWC, leaf Ψ, and vine size. Where SWC was very high, decreased 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 more berry monoterpenes.