The IPNW has emerged as a premium European wine grape growing region with Washington State as the dominant producer. Washington is second only to California in wine grape production in the United States [U.S. Department of Agriculture (USDA), 2011a]. In 2011, nearly 44,000 acres of wine grapes existed in Washington, a 395% increase over the last 18 years (USDA, 2011b). The region hosts 13 American Viticultural Areas (AVAs) acknowledged by the U.S. Alcohol and Tobacco Trade Bureau on the basis of national or local name recognition, usage, and distinguishing features (U.S. Alcohol and Tobacco Tax Trade Bureau, 2013). Several larger AVAs contain open land currently not planted to wine grape (Fig. 1).
Climate is the determinant limiting factor in wine grape production. Growing-degree day (GDD) accumulation is one common method of reporting climate and allows comparison between different locations under similar macroclimate. GDD accumulation for wine grapes is calculated as the summation of average temperatures [i.e., (maximum temperature + minimum temperature)/2] less a threshold of 10 °C between 1 Apr. and 31 Oct. In a major U.S. wine region, five grape type categories were developed based on this index of heat accumulation (Amerine and Winkler, 1944).
In temperate climates where heat accumulation is adequate to ripen wine grapes, winter cold damage may be the limiting factor for vineyard survival. Phenology, cultivar, and temperatures preceding potentially damaging low temperatures all influence risk of cold damage (Ferguson et al., 2011). Sites with lower extreme minimum temperatures will generally be at greater risk for cold damage, which can range from loss of fruitful buds to outright death of the entire vine. The typical minimum temperature threshold at peak dormancy for most wine grape cultivars is around −23 °C (Ferguson et al., 2011). Frost-free days (FFDs), the period between the last spring and first autumn frosts (0 °C), is frequently examined in determining the suitability of an area for wine grape production (Jackson and Cherry, 1988; Wolf and Boyer, 2003). FFDs indicate growing season length and serves as a proxy of the period over which wine grapes can develop and ripen.
Topography also plays a role in site suitability. Topographic suitability relates to the physical ability to manage a vineyard (i.e., ability for machinery to safely operate on a site) and influence over mesoclimatic (subregional to vineyard scale) conditions. Slope and aspect are both readily quantified topographic characteristics. In the Northern Hemisphere, slopes with a southern aspect have higher levels of insolation, and consequently heat accumulation, and are typically considered ideal; however, wine grapes can be successfully grown on aspects that are often considered “undesirable” (Wolfe, 1999). Because of this, the degree of slope is generally given greater consideration. Moderate slopes (5% to 15%) are considered the best sites for wine grape production as they allow air drainage without hindering equipment operation (Jones et al., 2004). Sloped sites can reduce cold air pooling as they promote air drainage to alternate locations. Sites located above potential cold air pools may also benefit from additional elevation through lower daytime temperatures, which can promote fruit quality in hot regions (Gladstones, 1992). Unfortunately, slope alone cannot predict mesoclimate conditions and sites must be considered within the greater context of surrounding topography, obstructions to air flow and prevailing winds (Jackson and Schuster, 2001).
Wine grapes tolerate a range of soil conditions. Waterlogged soils retard vine growth, hinder mechanical operations in the vineyard, and favor the development of several root diseases and chlorosis in calcareous soils (Davenport and Stevens, 2006). Free-draining soils maintain oxygen concentrations near roots and facilitate moderate water stress with proper irrigation management (Foss et al., 2010). Unrestricted soil drainage to a depth of at least 2 to 3 m is recommended for vineyards in most situations (Gladstones, 1992; Jackson, 2008). Failla et al. (2004) found grapevine (Vitis sp.) roots at depths of over 3 m in soil surveys in northern Italy. Vines may grow roots to depths of 30 m or more if no impenetrable barriers are present (Keller, 2010). Only under severe water stress will wine grapes access substantial water from greater than 2 m. Shallow soils above parent material or other impenetrable barriers where root penetration is problematic are considered unsuitable for grape production and increase the likelihood of waterlogging (Foss et al., 2010; Jackson, 2008). Well-drained soils, along with greater soil depth, encourages the growth of robust, perennial root structures. While the AWC of soils in the IPNW is relatively low to moderate, directed applications of irrigation allow for consistently high-quality grape production.
Soil pH is also important in wine grape production in Washington State, as wine grape is grown on its own roots. Absorption of many nutrients for wine grape is optimal at soil pH of 6.6 to 7.2 (Meinert and Curtin, 2005). Overly alkaline soils lead to deficiencies of phosphorus, iron, manganese, boron, and zinc (Gladstones, 1992). Overly acidic soils can generate toxic levels of aluminum, copper, and manganese; induce phosphorus deficiency; restrict root growth; and lead to grapevine nutrient and soil microbial imbalances (Bargmann, 2003; Foss et al., 2010; Gladstones, 1992).
The expansion of the IPNW wine grape industry has resulted in the inability of viticulture consultants and university Extension to travel to every potential new vineyard location. Efficient remote assessment of a site is necessary to facilitate this expansion and avoid potential pitfalls of a site that need to be addressed before vine establishment. This project was designed to establish a decision support system (DSS) for wine grape production in the IPNW to help facilitate these remote assessments.
The specific objectives of this project were to: 1) establish a DSS for wine grape that includes information on common site characteristics, such as topographic, edaphic, and climatic parameters; and 2) begin preliminary evaluation of the effectiveness of the DSS to elucidate potential problematic components in wine grape production by mapping existing vineyards and obtaining qualitative perceptions of vineyard performance from experienced viticulturists.
AgWeatherNet 2013 The Washington Agricultural Weather Network Version 2.0. 28 June 2013. <http://weather.wsu.edu/>
Bargmann, C.J. 2003 Geology and wine 7. Geology and wine production in the coastal region, western Cape Province, South Africa Geoscience Can. 30 161 182
Beaudette, D.E. & O'Geen, A.T. 2009 Quantifying the aspect effect: An application of solar radiation modeling for soil survey Soil Sci. Soc. Amer. J. 73 1345 1352
Daly, C., Halbleib, M., Smith, J.I., Gibson, W.P., Doggett, M.K., Taylor, G.H., Curtis, J. & Pasteris, P.P. 2008 Physiographically sensitive mapping of climatological temperature and precipitation across the conterminous United States Intl. J. Climatol. 28 2031 2064
Davenport, J.R. & Stevens, R.G. 2006 High soil moisture and low soil temperature are associated with chlorosis occurrence in Concord grape HortScience 41 418 422
Ellis, E.A., Nair, P.K.R., Linehan, P.E., Beck, H.W. & Blanche, C.A. 2000 A GIS-based database management application for agroforestry planning and tree selection Comput. Electron. Agr. 27 41 55
Evans, R.G. & Alshami, A.S. 2009 Pulse jet orchard heater system development: Part I. Design, construction, and optimization Trans. Amer. Soc. Agr. Biosystems Eng. 52 331 343
Failla, O., Mariani, L., Brancadoro, L., Minelli, R., Scienza, A., Murada, G. & Mancini, S. 2004 Spatial distribution of solar radiation and its effects on vine phenology and grape ripening in an alpine environment Amer. J. Enol. Viticult. 55 128 138
Ferguson, J.C., Tarara, J.M., Mills, L.J., Grove, G.C. & Keller, M. 2011 Dynamic thermal time model of cold hardiness for dormant grapevine buds Ann. Bot. (Lond.) 107 389 396
Foss, C., Morris, D., Burnside, N. & Ravenscroft, N. 2010 FIBRE SERIES: Champagne comes to England: Assessing the potential of GIS in the identification of prime vineyard sites in south east England. 20 Nov. 2013. <http://www.plumpton.ac.uk/upload/documents/departments/wine/research/research-champagne-comes-to-england .pdf>
Fu, P. & Rich, P.M. 2002 A geometric solar radiation model with applications in agriculture and forestry Comput. Electron. Agr. 37 25 35
Gladstones, J. 1992 Viticulture and environment. Winetitles, Adelaide, Australia
Jackson, D. & Schuster, D. 2001 The production of grapes and wine in cool climates. Gypsum Press, Wellington, New Zealand
Jackson, D.I. & Cherry, N.J. 1988 Prediction of a district’s grape-ripening capacity using a latitude-temperature index (LTI) Amer. J. Enol. Viticult. 39 19 28
Jackson, R.S. 2008 Wine science principles and applications. 3rd ed. Elsevier: Academic Press, Burlington, MA
Jones, G.V. & Duff, A.A. 2007 The climate and landscape potential for wine production in the north Olympic Peninsula region of Washington. Olympic Cellars, Port Angeles, WA
Jones, G.V., Duff, A.A. & Myers, J.M. 2006 Modeling viticultural landscapes: A GIS analysis of the viticultural potential in the Rogue Valley of Oregon. Proc. VIth Terroir Congr., Bordeaux and Montpellier, France, 3–7 July 2006: 256–261
Jones, G.V., Snead, N. & Nelson, P. 2004 Geology and wine 8. Modeling viticultural landscapes: A GIS analysis of terroir potential in the Umpqua Valley of Oregon Geoscience Can. 31 167 178
June, C. 2000 Design of an intelligent geographic information system for multi-criteria site analysis J. Urban Regional Info. Systems Assn. 12 5 17
Jurisic, M., Stanisavljevic, A. & Plascak, I. 2010 Application of geographic information system (GIS) in the selection of vineyard sites in Croatia Bulgarian J. Agr. Sci. 16 235 242
Keller, M. 2010 The science of grapevines: Anatomy and physiology. Elsevier: Academic Press, Burlington, MA
Kurtural, S.K., Dami, I.E. & Taylor, B.H. 2007 Utilizing GIS technologies in selection of suitable vineyard sites Intl. J. Fruit Sci. 6 87 107
Meinert, L. & Curtin, T. 2005 Terroir of the Finger Lakes of New York, p. 34–40. In: M. Ebehart (ed.). Proc. 18th Keck Res. Symp. Geol. Keck Geology Consortium, College of Wooster, Wooster, OH
Spayd, S. 1999 Industry panel discussion I: Working with wineries, p. 21–22. In: J. Watson (ed.). Growing grapes in eastern Washington. Proc. 1998 Washington State Univ. Shortcourse for Establishing a Vineyard and Producing Grapes. Good Fruit Grower, Yakima, WA
U.S. Alcohol and Tobacco Tax Trade Bureau 2013 American Viticultural Area (AVA). 28 June 2013. <http://www.ttb.gov/wine/ava.shtml>
U.S. Department of Agriculture 1993 Soil survey manual. U.S. Dept. Agr., Soil Conservation Serv. Hdbk. 18
U.S. Department of Agriculture 2011a Grape release. 15 Mar. 2013. <http://1.usa.gov/taiR8H>
U.S. Department of Agriculture 2011b Washington vineyard acreage report 2011. 15 Mar. 2013. <http://1.usa.gov/sYOar2>
Vineyard Site Suitability Analysis 2011 The basics of vineyard site evaluation and selection. 15 Mar. 2013. <http://bit.ly/u0vdSe>
Wolf, T.K. & Boyer, J.D. 2003 Vineyard site selection. Virginia Tech. Publ. No. 463-020
Wolfe, W. 1999 Site selection in eastern Washington: Optimizing site and variety choices, p. 27–30. In: J. Watson (ed.). Growing grapes in eastern Washington: Proc. 1998 Washington State University Shortcourse for Establishing a Vineyard and Producing Grapes. Good Fruit Grower, Yakima, WA
Zucca, A., Sharifi, A.M. & Fabbri, A.G. 2008 Application of spatial multi-criteria analysis to site selection for a local park: A case study in the Bergamo Province, Italy J. Environ. Mgt. 88 752 769