Relationships between vine water status, soil texture, and vine size were observed in four Ontario Pinot noir vineyards (2008–2009). The vineyards were divided into water status zones using geographic information systems to map the seasonal mean leaf water potential (ψ) and cane pruning weights (vine size). Leaf (ψ) zones were confirmed using k-means clustering. Both seasons were cooler and wetter than average and the range of leaf ψ defining the water status zones was narrow (−0.59 to −0.95 MPa across all vineyards). Yield, vine size, crop load, anthocyanins and phenols had highest coefficients of variability. Higher yields, berry weights, titratable acidity, anthocyanins, and color were occasionally associated with low water status zones. There were no berry composition variables with differences between vine size zones in all four vineyards. Higher yields, cluster numbers, and berry weights were frequently associated with high vine size zones. Principal components analysis separated the vineyards but did not create clusters based on leaf ψ or vine size. There were notable correlations between vineyard and grape composition variables, and spatial trends were qualitatively related for many of the variables. Significant r2 values suggested inverse relationships in 2008 were found for leaf ψ vs. anthocyanins, color intensity, and phenols as well as vine size vs. anthocyanins, while in 2009 there were significant r2 values for soil moisture vs. anthocyanins and color intensity that likewise suggested inverse relationships. This study showed that there is potential for using geomatic techniques to understand the variability in vineyards, but erratic weather in eastern North America presents a challenge for understanding the driving forces of that variability.
- geographic information systems
- global positioning systems
- soil moisture
- vine water status
- ©2017 by the American Society for Enology and Viticulture