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February 2017 WINES&VINES 83 WINE EAST GRAPEGROWING available in time to implement criti- cal management decisions. 22 The role of ground-based prox- imal sensors is to overcome many of the restrictions associated with satellite and/or airborne remote- sensing systems. 23 Generally, prox- imal sensing systems collect multispectral images in visible wavebands (i.e., the green and red) and in the near infrared (NIR), and then calculate vegeta- tion indices and make inferences about crop growth. 24 The most commonly used index for mapping variations in canopy density is the NDVI. As previously demonstrated with airborne spectral reflectance im- agery predicting vine size, 25 ground-based sensor measure- ments indicated a consistent as- sociation between vine size (i.e., pruning weight, an indicator of vine vigor) and NDVI over time in Merlot vineyards in northern Greece. 20 Ground-based sensors predicted the spatial variation of biomass production near vérai- son with variable precision; nev- ertheless, NDVI was correlated with vine size and best described by a quadratic regression. 20,23 Vine productivity in terms of yield was also predicted by ac- tive canopy reflectance sensors measuring NDVI in Greek vine- yards planted with Cabernet Sauvignon and Xinomavro. 26 In another study, a mobile mon- itoring system consisting of GreenSeeker optical sensors and ultrasonic sensors assessed the canopy health and vigor status of vines in Italian vineyards. 22,24 NDVI maps clearly identified differences in vegetation, whereby low vegeta- tion vigor (low NDVI values) cor- related with high incidence of grapevine downy mildew, and NDVI measurements correlated well with vine phytosanitary sta- tus. 22,24 Linear correlation to stable isotope content in leaves ( 13 C and 15 N) showed that canopy reflec- tance detected plant stresses as a result of water shortage and lim- ited nitrogen fertilizer uptake. 23 The implementation of geospa- tial technologies aims to promote vineyard management based on efficiency and quality of produc- tion and to explore vineyard vari- ability with respect to soil and vine water status, nutrient availability, plant health and disease inci- dence. 27 However, the usefulness of proximal sensing technology (in this case, the GreenSeeker technol- ogy) and its relationship with plant physiological measurements still has to be explored. The resulting outcomes of this research may allow a wider adoption of precision viticulture with greater focus on the best exploitation of vineyard spatial variability. Methods in brief Sites and cultivars; geoloca- tion: Three commercial vineyards were chosen in the Niagara Pen- insula of Ontario and included two blocks each of Cabernet Franc, Riesling and Pinot Noir (2-5 acres in area). The sites rep- resented the following sub-appel- lations: Creek Shores (Riesling and Cabernet Franc at Lambert Farms), St. David's Bench (Pinot Noir at Coyote's Run Estate Win- ery), Beamsville Bench (Riesling and Cabernet Franc at Cave Spring Cellars). Soil types 1 varied substantially in these sub-appella- tions from moderately well- drained Chinguacousy (Creek Shores and Beamsville Bench) to KEY POINTS Researchers in Ontario evaluated the usefulness of high spatial resolution proximally sensed observations acquired by GreenSeeker for mapping yield, vigor, vine water status and fruit composition in Ontario vineyards. The overall objective was to identify unique zones in the vineyards in terms of physiology, productivity and berry composition. GreenSeeker observations were collected from berry set to just prior to harvest by calculating the normalized difference vegetation index (NDVI). Higher NDVI values were associated with yield components and vine size, while lower NDVI values were correlated with several berry composition variables, suggesting that proximal sensing is a practical tool for vineyard vegetative growth surveys and grape composition inferences. Create a classic with our new 8 color UV custom glass printing technology. With the best bottle and closure brands on the market, our printed glass experts will work with you to launch your next best seller. Contact Waterloo Container today. Go ahead… judge a book by its cover. Toll Free: 888-539-3922 | waterloocontainer.com