Practical Winery
65 Mitchell Blvd, San Rafael, CA 94903
phone: 415-453-9700 ext 102
email: Office@practicalwinery.com
1 · 2 · 3 · 4
Spring 2011
GRAPEGROWING
Figure 4. A hand-held ceptometer was used to evaluate the amount of light filtering through the fruit zone of the canopy, to measure the microclimate of grapevines being tested.
Crop load and leaf area had significant effects on ripening. Mechanically box-pruned vines were slower to ripen grapes than spur-pruned canopies, especially in Pinot Grigio, but there were no adverse effects on fruit composition at harvest.
The only adverse effect of mechanical canopy management was delayed ripening of Pinot Grigio with leaf removal, attributed to the reduced leaf area to fruit ratio achieved by this practice.
Overall, control of yield was achieved by integrating mechanized canopy management. Winegrapes are said to be in-balance when the vine can grow its fruit from flowering to a target °Brix within a given summation of degree days.
The leaf area to fruit ratio of Syrah fell between 1.2 m2/kg for Syrah, and 1.0 m2/kg for Pinot Grigio when these vines were boxpruned, adjusted to medium shoot density, and had leaf removal on the east (morning) side of the fruit zone. These leaf area to fruit ratios are in line with the 0.8 to 1.2 m2 leaf area per kg of fruit needed to mature fruit trained to singlecanopy trellis systems in the San Joaquin Valley.16
   
Read this and more viticulture/enology studies by Fresno State University on their website.
The authors would like to acknowledge American Vineyard Foundation for partial funding, Bronco Wine Company for in-kind labor and land, and Oxbo International Corp. for use of the equipment and in-kind labor during the execution of the research.
Oxbo de-leafer with two heads to remove leaves from the morning side of a vine row where only one head is in operation, depending on the direction of travel in the vineyard.
References
1. Becker, N.J. 1966 Reaktionkinetische Temperaturinessungem in der Weinbaulichen Okologie. Weinberg und Keller 13: 501-512.
2. Bergvist, J.N., N. Dokoozlian, and N. Ebisuda. 2001 “Sunlight exposure and temperature effects on berry growth and composition of Cabernet Sauvignon and Grenache in the central San Joaquin Valley in California.” Am. J. Enol. & Vitic. 52: 1-7.
3. Dokoozlian, N.K., and W.M. Kliewer. 1995 “The light environment within grapevine canopies. I. Description and seasonal changes during fruit environment.” Am. J. Enol. & Vitic. 46: 209-218.
4. Dokoozlian, N.K., and W.M. Kliewer. 1996 “Influence of light on grape berry growth and composition varies during fruit development.” J. Amer. Soc. Hort. Sci. 121(5): 8695874.
5. Draganov, D., S. Pandeliev, and E. Antonov. 1975 “Research on heat loads of leaves and berries in vineyards with different training systems.” Grad. Lozar. Nauka 12: 147-156.
6. Draganov, D. and S. Pandeliev. 1976 “Heat loads of leaves and berries of the Bolgar cultivar in vineyards of different training systems. II. Night temperature regime.” Grad. Lozar. Nauka 13: 92-98.
7. English, J., A. Bledsoe, and J. Marois. 1990 “Influence of leaf removal from the cluster zone on the components of evaporative potential within grapevine canopies.” Agriculture, Ecosystems, and Environment 31(1): 49-61.
8. Gladstone, E.A. and N.K. Dokoozlian. 2003 “Influence of leaf area density and trellis/training systems on the microclimate within grapevine canopies.” Vitis 42: 123-131.
9. Harbertson, J.F., E.A. Picciotto, and D.O. Adams. 2005 Phenolic and Anthocyanin assay for Use with Spectrophotometer.” University of California, Davis.
10. Howell, G.S. 2001 “Sustainable grape productivity and the growth yield relationship: A review.” Am. J. Enol. & Vitic. 52: 165-174.
11. Jackson, R. 2000. Wine Science: Principles, Practice, Perception. Academic Press.
12. Kasimatis, A.N., L.A. Lider, and W.M. Kliewer. 1982 “Trellising and training practices to influence yield, fruit composition, and growth of Chenin Blanc grapes.” In A.D. Webb (Ed.), Proc. of the 1980 Univ. of California Davis Grape and Wine Centennial Symposium (pp. 386-389). Univ. of California, Davis.
13. Keller, M., R.P. Smithyman, and L.J. Mills. 2008 “Interactive effects of deficit irrigation and Cabernet Sauvignon grapevines in an arid climate.” Am. J. Enol. & Vitic. 59: 221-233.
14. Kennedy, J.A. 2008 “Grape and wine phenolics: Observations and recent findings” Cien. Inv. Agr. 35 (2): 107-120.
15. Kliewer, W.M. and R. Smart. 1988 “Canopy manipulation for optimizing vine microclimate, crop yield and composition of grapes.” In C. Wright (Ed.) Manipulation of fruiting. Proc. 47th Easter School in Agric. Sci. Symp., Univ. Nottingham (pp. 275-291). London: Butterworths.
16. Kliewer, M.W. and N. Dokoozlian. 2005 “Leaf area/crop weight ratios of grapevines: Influence on fruit composition and wine quality.” Am. J. Enol. & Vitic. 56 (2): 170-181.
17. Kurtural, S.K., B.H. Taylor, and I.E. Dami. 2006 “Effects of pruning and cluster thinning on yield and fruit composition of Chaºßmbourcin grapevines.” Hort Technology 16: 233-240.
18. Morris, J.R. 2007 “Development and commercialization of a complete vineyard mechanization system.” Hort Technology 17: 411-420.
19. Petrie, P.R. and P. Clingeleffer. 2006 “Crop thinning, grape maturity, and anthocyanins concentration: Outcomes from irrigated Cabernet Sauvignon in a warm climate.” Aust. J. Grape & Wine Research 12: 21-29.
20. Reynolds, A.G., R. M. Pool, and L.R. Mattick. 1985 “Effect of training system on growth, yield, fruit composition and wine quality of Seyval blanc.” Am. J. Enol. & Vitic. 36: 156-164.
21. Reynolds, A.G. and D. Wardle. 1993 “Yield component path analysis of Okanagan Riesling vines conventionally pruned or subjected to simulated mechanical pruning.” Am. J. Enol. & Vitic. 44: 173-179.
22. Reynolds, A.G. and J.E. Vanden Heuvel. 2009 “Influence of grapevine training systems on vine growth and fruit composition: A review.” Am. J. Enol. & Vitic. 60: 251-268.
23. Shaulis, N.J., H. Amberg, and D. Crowe. 1966 “Response of Concord grapes to light, exposure and Geneva double curtain training.” Proc. Am. Soc. Hortic. Sci. 89: 268-280.
24. Smart, R. 1982 “Vine manipulation to improve winegrape quality.” Proc. Grape and Wine Centennial Symp. June 1980 (pp. 362-375). University of California, Davis.
25. Smart, R.E. 1985 “Principles of grapevine microclimate manipulations with implications for yield and quality: A review.” Amer. J. Enol. & Vitic. 36: 230-239.
26. Smart, R. 1988 “Shoot spacing and canopy microclimate.” Am. J. Enol. & Vitic. 39: 325-333.
27. Smart, R.E. and M. Robinson. 1991 Sunlight into Wine: A Handbook for Winegrape Canopy Management. Adelaide, South Australia: Winetitles.
28. Tardaguila, J., P.R. Petrie, S. Poni, M.P. Diagio, and F.M. de Toda. 2008 “Effects of mechanical thinning on yield and fruit composition of Tempranillo and Grenache grapes trained to a vertical shoot positioned canopy.” Am. J. Enol. & Vitic. 59: 412- 417.
29. Vanden Heuvel, J., J. Proctor, J. Sullivan, and K. Fisher. 2004 “Influence of training/trellising system and rootstock selection on productivity and fruit composition of Chardonnay and Cabernet Franc grapevines in Ontario.” Am. J. Enol. & Vitic. 55: 253-264.
30. Van Zyl, J. and L. van Huyssteen. 1980 “Comparative studies on wine grapes on different trellising systems. II. Microclimatic studies grape composition and wine quality.” S. Afr. J. Enol. Vitic. 1: 15-25.
31. Williams, L.E. 2001 “Irrigation of winegrapes in California.” Practical Winery & Vineyard Nov/Dec 2001. (practicalwinery.com/novdec01p42.htm).
32. Winkler, A.J. and W.O. Williams. 1939 “The heat required to bring Tokay grapes to maturity.” Proc. Am. Soc. Hort. Sci. 37: 650-652.