In temperate climates where heat Developing a Wine Grape Site Evaluation accumulation is adequate to ripen Decision Support System for the Inland wine grapes, winter cold damage may be the limiting factor for vineyard Pacific Northwestern United States survival. Phenology, cultivar, and tem- peratures preceding potentially dam- 1 1,3 2 aging low temperatures all influence Ian-Huei Yau , Joan R. Davenport , and Michelle M. Moyer risk of cold damage (Ferguson et al., 2011). Sites with lower extreme min-
ADDITIONAL INDEX WORDS. remote site evaluation, site selection, viticulture, Vitis imum temperatures will generally be vinifera at greater risk for cold damage, which can range from loss of fruitful buds SUMMARY. Site selection is critical in wine grape (Vitis vinifera) production. The to outright death of the entire vine. wine grape industry is expanding in the inland Pacific northwestern United States The typical minimum temperature (IPNW) using traditional means of site evaluation including on physical examina- tion of topography, geomorphology, soil characteristics, and analysis of long-term threshold at peak dormancy for most observations from weather stations. Through the use of modeled spatial data, we wine grape cultivars is around –23 C present a geographic information system (GIS) representing environmental features (Ferguson et al., 2011). Frost-free important for evaluating vineyard site suitability for the production of wine grapes. days (FFDs), the period between Elevation, slope, insolation, heat accumulation, growing season length, extreme the last spring and first autumn frosts minimum temperature and the soil parameters of drainage, available water-holding (0 C), is frequently examined in capacity (AWC), depth to restrictive layer, and pH combine to represent composite determining the suitability of an area topographic, edaphic, and overall production suitability. Comparing modeled site for wine grape production (Jackson suitability predictions with existing vineyards, we found modeled data on site and Cherry, 1988; Wolf and Boyer, properties aligned with vineyard manager perceptions of production quality in 2003). FFDs indicate growing season established vineyards. Although remote spatial evaluation will never replace physical site examination for addressing specific site conditions, it allows an length and serves as a proxy of the efficient, spatially extensive, initial assessment of sites that can direct attention to period over which wine grapes can potentially problematic or distinguishing environmental characteristics. develop and ripen. Topography also plays a role in site suitability. Topographic suitabil- he IPNW has emerged as a recognition, usage, and distinguish- ity relates to the physical ability to premium European wine grape ing features (U.S. Alcohol and Tobacco manage a vineyard (i.e., ability for Tgrowing region with Wash- Tax Trade Bureau, 2013). Several machinery to safely operate on a site) ington State as the dominant pro- larger AVAs contain open land cur- and influence over mesoclimatic (sub- ducer. Washington is second only rently not planted to wine grape regional to vineyard scale) conditions. to California in wine grape produc- (Fig. 1). Slope and aspect are both readily quan- tion in the United States [U.S. De- Climate is the determinant lim- tified topographic characteristics. In partment of Agriculture (USDA), iting factor in wine grape production. the Northern Hemisphere, slopes with 2011a]. In 2011, nearly 44,000 acres Growing-degree day (GDD) accu- a southern aspect have higher levels of wine grapes existed in Washing- mulation is one common method of insolation, and consequently heat ton, a 395% increase over the last 18 of reporting climate and allows com- accumulation, and are typically con- years (USDA, 2011b). The region parison between different locations sidered ideal; however, wine grapes hosts 13 American Viticultural Areas under similar macroclimate. GDD can be successfully grown on aspects (AVAs) acknowledged by the U.S. accumulation for wine grapes is cal- that are often considered ‘‘undesir- Alcohol and Tobacco Trade Bureau culated as the summation of average able’’ (Wolfe, 1999). Because of this, on the basis of national or local name temperatures [i.e., (maximum temper- the degree of slope is generally given ature + minimum temperature)/2] greater consideration. Moderate slopes We thank all the cooperative growers who shared their less a threshold of 10 Cbetween vineyards and expertise to help validate this work. (5% to 15%) are considered the best Additional thanks to Dr. Greg Jones of Southern 1 Apr. and 31 Oct. In a major U.S. sites for wine grape production as Oregon University for his insight and assistance. wine region, five grape type cate- they allow air drainage without hin- Funding for this project was provided by the North- west Center for Small Fruits Research, the Washington gories were developed based on this dering equipment operation (Jones State Grape and Wine Research Group, and the index of heat accumulation (Amerine et al., 2004). Sloped sites can reduce Washington State University Agricultural Research and Winkler, 1944). cold air pooling as they promote air Center. The research described herein represents a portion of a thesis submitted by I. Yau to the Graduate School of Washington State University in partial fulfillment of requirements for the Masters of Science in Crop and Soil Sciences. Units 1Department of Crop and Soil Sciences, Irrigated Agriculture Research & Extension Center, Washing- To convert U.S. to SI, To convert SI to U.S., ton State University, 24106 N Bunn Road, Prosser, multiply by U.S. unit SI unit multiply by WA 99350-8694 0.4047 acre(s) ha 2.4711 2Department of Horticulture, Irrigated Agriculture 0.3048 ft m 3.2808 Research & Extension Center, Washington State 0.0929 ft2 m2 10.7639 University, 24106 N Bunn Road, Prosser, WA 2.54 inch(es) cm 0.3937 99350-8694 1.6093 mile(s) km 0.6214 3Corresponding author. E-mail: [email protected]. ( F – 32) O 1.8 F C( C · 1.8) + 32
88 • February 2014 24(1) Fig. 1. American Viticultural Areas (AVAs) of the inland Pacific northwestern U.S. AVA boundaries digitized from official descriptions in the Federal Register and corresponding georeferenced U.S. Geological Survey topographic maps. drainage to alternate locations. Sites of over 3 m in soil surveys in northern 1992). Overly acidic soils can generate located above potential cold air pools Italy. Vines may grow roots to depths toxic levels of aluminum, copper, and may also benefit from additional ele- of 30 m or more if no impenetrable manganese; induce phosphorus defi- vation through lower daytime tem- barriers are present (Keller, 2010). ciency; restrict root growth; and lead peratures, which can promote fruit Only under severe water stress will to grapevine nutrient and soil micro- quality in hot regions (Gladstones, wine grapes access substantial water bial imbalances (Bargmann, 2003; 1992). Unfortunately, slope alone can- from greater than 2 m. Shallow soils Foss et al., 2010; Gladstones, 1992). not predict mesoclimate conditions above parent material or other im- The expansion of the IPNW wine and sites must be considered within penetrable barriers where root pene- grape industry has resulted in the in- the greater context of surrounding tration is problematic are considered ability of viticulture consultants and topography, obstructions to air flow unsuitable for grape production and university Extension to travel to every and prevailing winds (Jackson and increase the likelihood of waterlog- potential new vineyard location. Effi- Schuster, 2001). ging (Foss et al., 2010; Jackson, cient remote assessment of a site is Wine grapes tolerate a range of 2008). Well-drained soils, along with necessary to facilitate this expansion soil conditions. Waterlogged soils re- greater soil depth, encourages the and avoid potential pitfalls of a site tard vine growth, hinder mechanical growth of robust, perennial root struc- that need to be addressed before vine operations in the vineyard, and favor tures. While the AWC of soils in the establishment. This project was de- the development of several root dis- IPNW is relatively low to moderate, signed to establish a decision support eases and chlorosis in calcareous soils directed applications of irrigation al- system (DSS) for wine grape pro- (Davenport and Stevens, 2006). Free- low for consistently high-quality grape duction in the IPNW to help facili- draining soils maintain oxygen con- production. tate these remote assessments. centrations near roots and facilitate Soil pH is also important in wine The specific objectives of this moderate water stress with proper grape production in Washington State, project were to: 1) establish a DSS irrigation management (Foss et al., as wine grape is grown on its own for wine grape that includes informa- 2010). Unrestricted soil drainage to roots. Absorption of many nutrients tion on common site characteristics, a depth of at least 2 to 3 m is rec- for wine grape is optimal at soil pH such as topographic, edaphic, and cli- ommended for vineyards in most sit- of6.6to7.2(MeinertandCurtin, matic parameters; and 2) begin pre- uations (Gladstones, 1992; Jackson, 2005). Overly alkaline soils lead to liminary evaluation of the effectiveness 2008). Failla et al. (2004) found deficiencies of phosphorus, iron, man- of the DSS to elucidate potential grapevine (Vitis sp.) roots at depths ganese, boron, and zinc (Gladstones, problematic components in wine grape
• February 2014 24(1) 89 TECHNOLOGY AND PRODUCT REPORTS production by mapping existing vine- were divided vertically whenever possi- SOIL CHARACTERISTICS. Thematic yards and obtaining qualitative percep- ble to maintain relatively constant mean maps of soil characteristics were cre- tions of vineyard performance from latitude for each county (±0.0001 ). ated for drainage class, depth to any experienced viticulturists. Vertical divisions were made with restrictive layer, AWC (0 to 50 cm), overlap to account for effects of ad- andpH(0to50cm).Dominant Materials and methods jacent topography and improved component or condition was used DEVELOPMENT OF DATA LAYERS. continuity. as the aggregation method. Counties Spatial data sources are summarized Calculations were made from represented with multiple SSURGO in Table 1. Geographic information ordinal day 91 to 304 (1 Apr. to databases were merged and clipped system software packages used were 31 Oct.). Thirty-two azimuth direc- to county boundaries. Vector data ArcGIS (versions 9.3.1 and 10.0; tions were used to calculate the were converted to raster data with a Esri, Redlands, CA). Tabular data viewshed. Eight zenith and azimuth resolution of 10 m to adequately were spatially represented using geo- divisions were used to calculate the represent soil map unit boundaries graphic coordinates provided by re- sky map. A uniform sky diffuse radi- and match DEM resolution. sponsible organizations. Spatial data ationmodelwasusedwithadiffuse CLIMATIC CHARACTERISTICS. A were projected to United Transverse proportion of 0.3 and transmissivity surface of GDD accumulation was Mercator Zone 11 North, North of 0.5, presumptive of generally clear calculated using Parameter-Elevation American Datum, 1983 using bilinear sky conditions (Fu and Rich, 2002). Regressions on Independent Slope sampling for continuous data where Insolation surfaces do not represent Model (PRISM) monthly normal sum- necessary. Thematic maps were cre- actual solar accumulation over a cli- mations from 1971 to 2000. PRISM ated from Soil Survey Geographic matically relevant period of record produces official climate data sets for (SSURGO) databases using Soil Data and are intended to represent sites’ the USDA using a vast network of Viewer (version 5.2; Natural Resources topographic exposure. Output sur- weather stations, relying on a large Conservation Service, Lincoln, NE). face units are Watt-hours per square community of climate experts and TOPOGRAPHIC CHARACTERISTICS. meter. modeling numerous environmental Slope and insolation were calculated Site exposure is traditionally char- factors influencing climate including using the National Elevation Dataset acterized by aspect, typically divided elevation, aspect, coastal proximity, digital elevation model (DEM), 1/3 symmetrically, establishing a hierar- and moist boundary layer heights arc second resolution (10 m). Slope chy of desirable slope orientations (Daly et al., 2008). Monthly GDD calculations were made in units of (Jones et al., 2004; Smith, 2002; information was calculated by taking percent rise. Insolation calculations Wolf and Boyer, 2003). Simple as- the average of the monthly maxi- were performed using the mean lati- pect calculations do not account mum and minimum temperature tude of each DEM to 10–12 decimal for dynamic shading from adjacent normals, subtracting a base temper- degrees, a sky size of 40,000 cells, topography throughout a day and ature of 10 C, and multiplying by 14-d and 2-h intervals. growing season, or solar angles at the number of days in the month. Calculation guidelines recom- different latitudes. In a topographi- Heat accumulation was summed by mend the extent of input DEMs be cally dissected landscape, as is found this method for 1 Apr. through 31 Oct. less than 1 latitude, but calculations in much of the wine grape growing (Amerine and Winkler, 1944). of adjacent surfaces with combined regions of the IPNW, insolation calcu- Surfaces of PRISM mean extreme extents of much less than 1 latitude lations assess the effects of nearby land- minimum temperatures (MEMTs) showed notable differences in conti- forms and provide a more continuous from 1961 to 2000 were examined nuity. Most DEMs masked by county surface of site exposure (Beaudette to rate cold damage risk. A surface were too large for a single calculation and O’Geen, 2009; Jones and Duff, of median FFDs from 1971 to 2000 of insolation. Digital elevation models 2007; Jones et al., 2006). was calculated by subtracting PRISM
Table 1. Summary of spatial data sources used in the development of a decision support system for wine grape site evaluation. Data setz Sourcez Data type Resolution/scaley National Elevation Dataset USGS Raster 1/3 arc second (10 m) Soil Survey Geographic database USDA-NRCS Vector 1:12,000 to 1:63,360 Parameter-Elevation Regressions PRISM Climate Group, Raster 15 arc seconds (400 m)x, on Independent Slopes OR State University 30 arc seconds (800 m)w, Model (PRISM) 1.25 arc minutes (2 km)v Esri world imagery Esri, i-cubed, USDA-FSA, Raster £1m,‡1:1, 128u USGS, AEX, GeoEye, AeroGRID, Getmappingz zUSGS (U.S. Geological Survey), USDA-NRCS (USDA-Natural Resources Conservation Service), PRISM (OR State University, Corvallis), Esri (Redlands, CA), i-cubed (Fort Collins, CO), USDA-FSA (U.S. Department of Agriculture-Farm Service Agency), AEX (Aerials Express, Seattle, WA), GeoEye (Appollo Mapping, Boulder, CO), AeroGRID (Hartley Wintney, United Kingdom), Getmapping (Hartley Wintney, United Kingdom). y1 m = 3.2808 ft, 1 km = 0.6214 miles. xMedian last spring and first fall frosts. wMonthly mean maximum and minimum temperatures. vMean annual extreme minimum temperatures. uAerial imagery resolution and source is dependent upon the scale at which it is viewed.
90 • February 2014 24(1) surfaces of median last spring frost or the ability to mechanize as many primary production goal is typically date from median first fall frost date. vineyard operations as possible, fa- maximizing yield while maintaining Monthly maximum and minimum voring the Jones method. Insolation quality above a minimum threshold temperature normals are available for ratingsweredevelopedbyusingthe that is quantifiable with some objec- free. Median frost date and MEMT midlatitude counties in the study tive metric. With ‘‘premium’’ wine surfaces were purchased from The area. Using ArcGIS, five quantile di- grape, other factors beyond yield are Climate Source, Inc. (Corvallis, OR). visions were calculated and the mean the primary components of per- RANKING SITE CHARACTERISTICS value for each quantile was then ceived quality. Perceptions of quality FOR DATA LAYERS. The data layers ranked from 1 to 5. may be strongly influenced by mar- discussed above were ranked into Soil drainage classes were ranked keting, and the relationship growers ranges indicating preference, designed similarly to Jones and Duff (2007), establish and foster with wineries to be used for quick evaluation of Jones et al. (2004, 2006), Kurtural (Spayd, 1999). a given site. The site evaluation DSS et al. (2007), and Vineyard Site Suit- V INEYARD SITES FOR DSS also maintained data layers of raw ability Analysis (2011). Soils that are EVALUATION. The ability of the DSS information to allow the user to pre- wet at shallow depths for significant to indicate potential issues for wine cisely determine why a particular periods during the growing season grape production was examined in 13 component ranked high or low in and those in which internal free water Washington vineyards, representing a given category. This contrasts with is rare or excessively deep received the Yakima Valley, Horse Heaven more common Boolean approaches the lowest ranks (USDA, 1993). This Hills, Red Mountain, Wahluke Slope, to site evaluation, which set ranges is intended to balance vines’ aversion Walla Walla Valley, and Ancient Lakes for parameters resulting in binary to saturated soil conditions with the AVAs. These existing vineyards were suitability surfaces indicating merely soil’s ability to retain irrigation water mapped by wine grape cultivar with ‘‘suitability’’ or ‘‘unsuitability’’ (Foss for a reasonable duration. a combination of GPS, aerial imagery, et al., 2010; Jurisic et al., 2010). Rankings for AWC are similar and georeferenced maps provided by Determining which spatial data to those of Jones et al. (2004) and growers. Sites were selected based on sets to use in building a site eval- weighted more toward higher AWC perceived wine grape quality, age of uation GIS database is finding the than proposed values in Wolf and the vineyards, or frequency of dam- intersection between what data are Boyer (2003). Jones et al. (2004) aging weather events. Growers were available and which parameters are performed site suitability analysis in interviewed between Sept. 2010 and most often perceived to be associated the Umpqua Valley, OR, where irri- Sept. 2012 regarding perceptions of with site suitability (Ellis et al., 2000; gation is not obligatory and there- vineyard performance, specifically is- Zucca et al., 2008). Understanding fore a minimum threshold of 0.10 sues relating to mapped environ- viticulture systems and prioritizing cmÁcm–1 is proposed. We did not mental variables, and planting dates. the influence of spatially represented adhere to this threshold because of Ground truthing focused largely on parameters is the first step in design- the necessity of irrigation in the qualitative assessment and viticultur- ing intelligent, GIS-integrated anal- IPNW. Depth to restrictive layer and ists’ responses during interviews. This ysis tools (June 2000). Component soil pH follow rankings similar to method of model evaluation was spe- ratings are summarized in Table 2. those of Wolf and Boyer (2003) who cifically chosen over a more empirical Slope rankings are the same as give ideal ranges, but not specific approach because of the inherent work done by Jones et al. (2006). numeric rankings. Similar minimum nature of vineyard variability that is Foss et al. (2010) allowed for much depths are recommended by Vineyard introduced when considering man- steeper slopes, up to 45 or 100%, in Site Suitability Analysis (2011). agement and reactionary production their Boolean analysis presuming Assessing a site evaluation model approaches of different vineyard man- nonmechanized operation for much for wine grape is not as straightfor- agers. In total, 570 ha were map- of this range, but larger production in ward as for other agricultural crops. ped. A summary of the vineyards used the IPNW is based on mechanization, For most other commodities, the in ground truthing are in Table 3.
Table 2. Rating system for wine grape site suitability used in the decision support system. Here, a ‘‘0’’ indicates low suitability and a ‘‘4’’ indicates high suitability for the production of wine grapes. Rating Site characteristicz 0 1 2 3 4 NoDatay Slope (%) <1, 26–30 1–5, 16–25 6–15 — — >30 Insolation (kW-h/m2) <969 970–1027 1028–1065 1066–1104 >1104 — Drainagex ED, SPD, PD, VPD SED WD MWD — — — AWC (cmÁcm–1) <0.075, >0.25 0.21–0.25 — 0.16–0.20 0.075–0.15 — Depth (cm) 0–50 51–100 >100 — — — pH <6.0, >8.0 6.1–6.5, 7.6–8.0 6.6–7.5 — — — z1 kW-h/m2 = 0.0929 kW-h/ft2, 1 cm = 0.3937 inch. yA rating of ‘‘NoData’’ removes an area from consideration. xED = excessively drained, SPD = somewhat poorly drained, PD = poorly drained, VPD = very poorly drained, SED = somewhat excessively drained, WD = well drained, MWD = moderately well drained, AWC = available water-holding.
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Table 3. Summary of vineyards and their locations used to ground truth a wine grape site evaluation decision support system for the inland Pacific northwestern United States. Additional outstanding or notable features are also included. Area (ha)z Predominate cultivar(s) Planting date(s) Outstanding features Yakima Valley AVAy Vineyard 1 21.7 Cabernet Sauvignon, Merlot 1991 Atypical placement of wind machines Vineyard 2 58.5 Chardonnay, Pinot Gris, 1986, 2006, 2008 Shift toward white cultivars, Riesling high soil pH Horse Heaven Hills AVA Vineyard 3 46.5 Cabernet Sauvignon, Merlot 2006, 2007 Cold damage Red Mountain AVA Vineyard 4 54.5 Cabernet Sauvignon, Syrah 1975–1998 Price premium, changes in cultivars, cultivar diversity Vineyard 5 49.6 Cabernet Sauvignon, Merlot 1984–2010 Price premium Wahluke Slope AVA Vineyard 6 26.7 Riesling, Cabernet Sauvignon 1999 Cold damage Vineyard 7 37.4 Cabernet Sauvignon 2003 Soil depth, insolation Vineyard 8 49.2 Cabernet Sauvignon, 2000 Available water-holding Merlot, Syrah capacity, insolation Vineyard 9 33.2 Cabernet Sauvignon 1999 Heat accumulation, bulk production Walla Walla Valley AVA Vineyard 10 0.4 Cabernet Sauvignon 2000 Cold damage, warmer Vineyard 11 3.5 Cabernet Sauvignon 1999 Cold damage Ancient Lakes AVA Vineyard 12 3.9 Roussanne 1991–2003 Heat accumulation, cultivar selection Vineyard 13 182.1 Riesling, Chardonnay, 1999–2002, 2005, 2010 Soil depth, cultivar diversity Gewu¨rztraminer z1 ha = 2.4711 acres. yAVA = American Viticultural Area.
Results and Discussion elevation, but elevation is always insolation, heat accumulation, cold Topographic characteristics examined when this DSS is used by air pooling, or air drainage). The varied Although slope and insolation practitioners for site assessment. spatial resolutions of the three cli- were the two derived surfaces primar- matic data sets all provide informa- Soil characteristics ily used in rating sites, aspect was also tion at meso- to macroclimatic scales. Soil map units in the SSURGO maintained in the GIS so users can Therefore, it is important to examine database are discrete units and the soil determine if low insolation at a site is climate data at sites through the characteristics we examined often due to slope orientation or hillshade context of topographic features with showed abrupt differences in adjacent effects. Insolation surfaces revealed an understanding of weather dynam- map units. Although this is certainly ics for a more realistic prediction of greater insolation at lower latitudes possible, it is more common to see site conditions. despite longer daylength at higher lat- more gradual shifts in soil character- itudes because of solar angle (Fig. 2). istics not easily represented in the Vineyard sites for DSS evaluation Elevation is also an important original vector data. We converted GDD and FFD surface extrac- consideration in vineyard site suit- the vector data to raster data to tions for mapped cultivars are sum- ability. Ideal elevation ranges should facilitate reclassification to compo- marized in Table 4. Cultivars with be low enough to ensure adequate nent ratings, but these data sets more than 10 ha mapped were sum- heat accumulation for consistent fruit should not be misinterpreted as con- marized individually; all else were ripening while avoiding frost pockets tinuous data sets. aggregated into ‘‘other reds’’ and that result from katabatic cold air ‘‘other whites.’’ flow (Foss et al., 2010; Jones et al., Climatic characteristics The most widely planted of the 2004; Kurtural et al., 2007; Wolf and Assessing the capability of a site 24 mapped wine grape cultivars, Boyer, 2003). These ranges are region to ripen wine grape and its risk of cold Cabernet Sauvignon was ranked sec- specific and depend on mesoclimate damage is best done at the meso- ond for greatest mean GDD (1505 C), and local topographic variability. Over climatic scale, ideally with multiple and third for greatest mean FFD a large, topographically diverse area weather stations within a single (175 d). ‘Riesling’, the second-most like the IPNW, elevation range rat- vineyard. Topographic features can planted cultivar, recorded the fifth ings would vary based on subregion. have substantial influences on a site’s greatest mean GDD (1408 C) and Sites have not been rated based on mesoclimatic characteristics (e.g., was tied with three other cultivars at
92 • February 2014 24(1) Fig. 2. Solar insolation summation from 1 Apr. to 31 Oct. for the inland Pacific northwestern U.S. calculated from 10-m (32.8 ft) National Elevation Dataset digital elevation model. Solar insolation is higher at lower latitudes despite longer daylength at higher latitudes because of solar angle; 1 kW-h/m2 = 0.0929 kW-h/ft2.
Fig. 3. Comparisons between raw data and site characteristic ratings for ground truthing Vineyard 1 as viewed in ArcGIS (Esri, Redlands, CA). Note that the rating scale is from 0 (low) to 4 (high) for degree of suitability for wine grape production: Cha = ‘Chardonnay’, CS = ‘Cabernet Sauvignon’, Mer = ‘Merlot’; 1 kW-h/m2 = 0.0929 kW-h/ft2,1cm= 0.3937 inch.
• February 2014 24(1) 93 TECHNOLOGY AND PRODUCT REPORTS
Table 4. Summary of growing-degree day (GDD) and median frost-free day (FFD) for the period of 1971 to 2000 by wine grape cultivars in vineyards used for ground truthing a wine grape site evaluation decision support system. GDD ( C)z FFD (d) Wine grape cultivar Area (ha)z Mean Range (±) Mean Range (±) Cabernet Sauvignon 142.4 1505 383 175 67 Merlot 65.1 1500 387 173 35 Syrah 44.7 1532 258 177 20 Other redsy 47.3 1491 258 174 19 Riesling 106.5 1408 203 174 20 Chardonnay 74.8 1397 204 171 29 Gewu¨rztraminer 29.1 1394 69 174 16 Pinot Gris 28.6 1391 63 169 16 Sauvignon Blanc 14.4 1402 154 171 16 Other whitesx 14.6 1483 286 176 24 z1 ha = 2.4711 acres, (1.8 · C) + 32 = F. yWine grape cultivars classified as ‘‘other red’’ in descending order by area mapped: Malbec, Cabernet Franc, Grenache, Mourve`dre, Sangiovese, Petit Verdot, Roussanne, Barbera, Dolcetto, Durif, Zinfandel, Nebbiolo, Pinot Noir, and Counoise. xWine grape cultivars classified as ‘‘other whites’’ in descending order by area mapped: Se´millon and Viognier. fourth for greatest mean FFD (174 d). its wind machines was at the highest Vineyards 2 and 3. The vineyard soils ‘Chardonnay’, the third-most planted elevation in the vineyard. Past vineyard are classed as well drained. Soil Survey cultivar, recorded the sixth greatest managers observed the greatest cold Geographic data also corroborated GDD (1397 C) and was tied with damage at the top of this vineyard. the viticulturist’s observations of rel- Sauvignon Blanc as the eighth great- Typically, wind machines are placed ative soil depth with a mean depth to est mean FFD (171 d). ‘Merlot’, at the lower elevations where cold air restrictive layer of 94.4 cm compared the fourth-most represented culti- is anticipated to accumulate to help with 140.3 cm in Vineyard 2 and at var, ranked third greatest mean GDD break and mix atmospheric inver- least 201 cm in Vineyard 3. (1500 C) and seventh in greatest sions, preventing damaging frosts and VINEYARD 2. A piece southeast mean FFD (173 d). All rankings were freezes (Evans and Alshami, 2009). of Vineyard 2 went unplanted after based on main cultivars and did not However, this unusual placement was soil tests revealed high salinity and include the red and white ‘‘other’’ due to a valley to the north of Vineyard pH. Again, SSURGO data aligned categories. 1 that fills with cold air, which fre- with the viticulturist’s observations; Many of the wine grape cultivars quently spills over to the top of the the unplanted southeastern portion mapped in this study comprise a small vineyard. of the vineyard was mapped with a pH area. Several cultivars only represented Mean extreme minimum temper- of 8.6. The ‘Riesling’ in Vineyard 2 small blocks within single vineyards. atures were slightly lower (0.2 C) in was designated for late harvest re- Sixteen of the mapped cultivars cov- the northern end of Vineyard 1 where quiring at least 24% soluble solids. ered less than 10 ha. This is the the wind machines are placed com- Compared with Vineyard 1, Vineyard beginning of an effort to further un- pared with the southern end. FFD 2 recorded 10 more FFD (mean of derstand ranges of climatic require- data also indicated a slightly shorter 160 d) and 102 C more GDD (mean ments of the large number of wine growing season at the northern end of of 1360 C). These factors may con- grape cultivars capable of producing Vineyard 1, 149 d compared with 151 d tribute to the ‘Riesling’s’ designation premium wines in the IPNW. As at the southern end of the vineyard. for late harvest. Although MEMT more vineyards are mapped by culti- This is an unusual circumstance, but were nearly the same as those found var with an understanding of crop these relatively small differences over in Vineyard 1 (mean of –17.4 C), quality and past cultivar changes, a relatively short distance in data sets cold damage was not noted as a fea- recommendations of climatic require- of these spatial resolutions are not ture in Vineyard 2. ments may be more specifically de- inconsequential. veloped for the IPNW and its Vineyard 1 had the fewest GDD Horse Heaven Hills AVA subregions. (mean of 1258 C) and the fewest VINEYARD 3. The viticulturist Ground truthing vineyards are FFD (mean of 150 d) of all ground noted deep, uniform, sandy loam soils discussed below with regard to features truthing vineyards, indicating the throughout the vineyard, greater noted by viticulturists and how they broad climatic range capable of sup- AWC than Vineyard 1 and 100% compare with mapped characteristics. porting certain wine grape cultivars. primary bud loss following a Nov. This site has grown ‘Merlot’ and 2010 freeze that dropped tempera- Yakima Valley AVA ‘Cabernet Sauvignon’ for 20 years tures as low as –23 C (AgWeatherNet, VINEYARD 1. An example of and is cooler than ground truthing 2013). Mean AWC was nearly the large-scale maps of Vineyard 1 is pre- vineyards producing ‘Gewu¨rztraminer’ same between Vineyard 3 and Vineyard sented in Fig. 3. Reclassified, rated and ‘Pinot Gris’. 1, slightly higher in the former, but surfaces in the GIS database provide Data from the soil survey maps total available water increases with a quick assessment of a site and raw confirmed the viticulturist’s percep- greater depth. Typical of the Horse data explain the ratings. This vineyard tions of good soil drainage and rela- Heaven Hills AVA, Vineyard 3 expe- was unusual in that the placement of tively shallow soils compared with rienced a relatively long growing
94 • February 2014 24(1) season with a mean of 172 FFD. of the vineyard and a segment of above the depositional area of the Compared with Vineyard 1, mean ‘Cabernet Sauvignon’ suffering from Missoula Floods. The viticulturist MEMT is 1.4 C warmer in Vineyard low vigor and poor fruit set (shatter), noted that it is much warmer than 3 (mean of –16.1 C). However, the perceived to be related to excessive Vineyard 6. Soil Survey Geographic vineyard’s gentle slopes (mean of drainage and/or low AWC. Although data showed a mean depth of 68 cm 1.8%) could exacerbate cold damage the vineyard is found on the western in the vineyard, far less than the during extreme years by allowing edge of the Red Mountain AVA, 174 cm mean in the Wahluke Slope cold air to linger. Although equipped which descends steeply to the west, AVA. Heat accumulation data actu- with wind machines, frost protection much of the central, eastern, and ally shows Vineyard 7 was cooler beyond a certain threshold can be northern portions of the vineyard than Vineyard 6, a difference of extremely costly or impossible. Heat are flat (mean slope of 3.3% and 115 C. However, Vineyard 7 did accumulation was greater in Vine- 1002 kW-h/m2 of insolation). This have predominately south-southwest yard3thanVineyards1and2(mean may contribute to cold air pooling, facing slopes, whereas Vineyard 6 of 1485 C). which could result in cold damage was both flat and variable in aspect. during vine dormancy. Modeled climatic data offers insight Red Mountain AVA Soil Survey Geographic data did of spatial extents typically unavailable VINEYARD 4. The viticulturist not reveal perceived vigor and shatter through examination of weather sta- noted outstanding performance from issues. AWC over the vast majority tion data, but an understanding of ‘Roussanne’ and ‘Mourve`dre’ and of the vineyard was 0.19 cmÁcm–1, uncertainty associated with model- poor vigor and ripening in one greater than what is rated as ideal, ing processes is critical. The scale at ‘Cabernet Sauvignon’ block, which but not generally considered exces- whichclimaticdatasetsaremodeled was under consideration for removal, sive. There is a small area classed do not reflect microclimatic condi- potentially because of excessive soil as somewhat excessively drained and tions most directly influencing vine drainage. Once again, SSURGO data with AWC of 0.11 cmÁcm–1, which development and performance, but corroborates viticulturist perceptions actually falls into the most highly coupled with topographic data, a syn- rating over half of the vineyard as rated range, but it is 300 m south- thesis of climatic features important having excessively drained soils, in- east of the area with shatter problems. to growers is possible. cluding the problematic ‘Cabernet One characteristic of this site not Gentle slopes (mean of 3.6%) Sauvignon’ block and slightly high captured in modeled data are persis- combined with latitude result in pH (mean of 7.6). An area along the tent wind, which may lead to higher moderate insolation values (mean of southwestern edge of the vineyard evapotranspiration in vines, exasper- 1039 kW-h/m2). Again, cold damage often experiences cold air drainage ating water stress related to excessive was not noted in Vineyard 7 despite problems. A flat area extending to soil drainage. Vineyard 5 had a mean an MEMT 0.3 C lower than in the west before declining briefly and GDD of 1520 C, 177 mean FFD, Vineyard 6 (mean of –17.6 C). A flattening out again may not allow and mean MEMT of –16.7 C. slightly shorter growing season (mean properairdrainageortheremay of 168 d) may once again contribute be a feature too small for the 10 m Wahluke Slope AVA to the site’s ability to withstand DEM to capture. Slopes were also VINEYARD 6. The viticulturist colder temperatures. Soil pH was relatively shallow (mean of 2.8%), stated this vineyard was under con- high, 8.1 to 8.7 according to which may contribute to cold air sideration for removal because of SSURGO data. About half the vine- pooling and the sixth least insolation persistent cold damage during vine dor- yard was classed as somewhat exces- of ground truthing vineyards (mean mancy. During the 23–25 Nov. 2010 sively drained. of 1015 kW-h/m2). Mean extreme freeze, ‘Merlot’, ‘Cabernet Sauvignon’, VINEYARD 8. The viticulturist minimum temperatures were compa- and ‘Syrah’ suffered 100% primary noted the site’s low AWC in sandy rable to those found in Vineyard 3 bud loss, whereas ‘Riesling’ was not soils, great depth to restrictive layer, (mean of –16.5 C). severely damaged. Most telling in and high heat accumulation. Accord- Several blocks in Vineyard 4 the spatial data were the exception- ing to SSURGO data, the vineyard’s have been converted to different wine ally flat terrain, a mean slope of soils were mostly excessively drained grape cultivars over the vineyard’s 0.5% and a maximum of only 1.7%, with small portions classed as some- history. ‘Chenin Blanc’ was replaced with shallow slopes surrounding what excessively drained. Soils were with ‘Merlot’ and ‘Grenache’ because the vineyard, preventing sufficient also somewhat alkaline (pH 7.4 to of low price, ‘Chardonnay’ and cold air drainage. Mean extreme 7.9) and AWC was relatively low ‘Gewu¨rztraminer’ performed well, minimum temperatures were com- (0.09 cmÁcm–1), but this actually falls but also were removed due to low parable to Vineyards 1 and 2 (mean into the ideal range according to our price, and ‘Riesling’ was replanted of –17.3 C), but the growing season ratings. Soils were deep with a mean with ‘Syrah’. This again illustrates in Vineyard 6 was an average of 23 d exceeding 200 cm. Vineyard 8 the malleability of cultivars to adapt longer (mean of 173 FFD), which recorded the second highest GDD to climatic conditions at a given site mayinfluencevinedormancyand (mean of 1603 C). The site was with the appropriate management. ability to withstand low tempera- dominated by west- and southwest- VINEYARD 5. The viticulturist tures. Vineyard 6 recorded a mean facing slopes, which may additionally pointed out high vigor in southern GDD of 1534 C. increase heat accumulation. Slopes blocks, an area that suffers from cold VINEYARD 7. The vineyard sits were rated favorably for much of the damage in a southeastern portion atop shallow, ancient soils, which lies vineyard, but the western and eastern
• February 2014 24(1) 95 TECHNOLOGY AND PRODUCT REPORTS blocks lay on relatively gentle slopes VINEYARD 11. Theonlynoted fractured caliche´ (hardened deposits (mean of 5.3%). Vineyard 8 had more feature of this vineyard is cold dam- of calcium carbonate) on the ridge, FFD (mean of 181 d) and warmer age during vine dormancy. Vineyard where the vineyard is situated. Soil MEMT (mean of –16.9 C) than other 11 is a flat vineyard; the vast majority depth was again corroborated by vineyards in the Wahluke Slope AVA. is <2% slope. This site recorded the SSURGO data, a mean of 55 cm and VINEYARD 9. The viticulturist most FFD with a mean of 217 d and a minimum of 18 cm. Shallow soils stated this vineyard primarily goes is tied with Vineyard 10 as having were found on topographically high toward bulk production and noted the third lowest MEMT (mean of points, where AWC was also noted high heat accumulation on the site. –18.1 C). The relatively long grow- to be low. Soil Survey Geographic Vineyard 9 had the highest GDD ingseasonandlowMEMTinVine- data showed a mean of 0.15 cmÁcm–1 (mean of 1605 C) of all ground yards 10 and 11 may contribute and a minimum of 0.13 cmÁcm–1, truthing vineyards. Western-facing to persistent cold damage problems both at the upper end of the ideal slopes may contribute to heat accu- by not allowing adequate time for range. mulation through collection of radia- vines to harden (Keller, 2010). Pre- Slopes were very gentle (mean of tion in the afternoon, but the site was dominately north-facing slopes re- 1.1%) and insolation was highly vari- rated relatively low in insolation sult in moderate insolation ratings able (mean of 1030 kW-h/m2) within (mean of 1003 kW-h/m2) because (mean of 1029 kW-h/m2). Accord- Vineyard 13. Much of the site was of gentle slopes and latitude. Declin- ing to SSURGO data, soils were well rated lower because of gentle slopes. ing in elevation from east to west, drained, moderately alkaline (pH Despite the high latitude (47.121 N), Vineyard 9 was rated as having favor- 7.7), had AWC at the upper end of the vineyard included areas rated mod- able slopes in the center of the vine- what is rated ideal and depth exceed- erately high in insolation (mean of yard, but the eastern and western ing 200 cm. Vineyard 11 recorded 1032 kW-h/m2). The southern half ends lie on relatively gentle slopes 1603 CGDD. of the site is alkaline (pH 7.8 to 8.1) (mean of 4.3%). Soils were mostly according to SSURGO data and the excessively drained and somewhat al- Ancient Lakes of the Columbia entire vineyard was classed as well kaline (pH 7.4 to 7.6). Growing Valley AVA drained. Vineyard 13 was tied with season length (mean of 182 FFD) VINEYARD 12. Water demand in Vineyard 12 as having the lowest and MEMT (mean of –16.5 C) were these vines is a persistent challenge. MEMT (mean of –20.3 C) and has comparable to those in Vineyard 8. The viticulturist claimed the site is a similar growing season (176 d), but warmer than its immediate vicinity. recorded 88 CfewerGDD. Walla Walla Valley AVA ‘Roussanne’, ‘Syrah’, and ‘Cabernet VINEYARD 10. The viticulturist Franc’ were noted as the best per- Conclusions noted cold damage during vine dor- formers and the easiest to grow, Vineyard site selection is a pre- mancy has been very problematic with whereas the ‘Merlot’ had proved planting process that influences com- the majority of vines suffering severe more challenging. Soil Survey Geo- mercial success of the vineyard (Smith, cold damage in three seasons. ‘Merlot’ graphic data classed most of the vine- 2002). It is rare to find a site that is and ‘Viognier’ have been removed yard as somewhat excessively drained, ideal in all facets of consideration; from the vineyard because of persistent and mean AWC over the vineyard is site selection optimizes the establish- frost issues. The wind machine was 0.11 cmÁcm–1, which again falls in our ment of a vineyard-given location noted as marginally effective. It was ideal range. Mean GDD in the vine- constraints. Nearly all factors given also noted soils were well drained. Soil yard was 1497 C and this decreases consideration have complex interac- drainage corresponds again with 150 C within 1500 m to the north- tions with one or more other factors. SSURGO data. Although much of west and southeast. Sites are selected based on a series of thesiteissituatedonslopesratedas ‘Cabernet Franc’ and ‘Syrah’ calculated risks associated with less- ideal, an air drainage alley adjacent to blocks received relatively high com- than-optimal conditions, and stan- the vineyard and the flat topography ponent ratings because of favorable dard agriculture best practices are on the other side of the air drainage slopes (mean of 13.8%) and insola- then superimposed to help alleviate alley appear to cause frequent cold air tion (mean of 1033 kW-h/m2). The site faults. pools at this vineyard. Steep slopes in ‘Merlot’ blocks were rated lower be- Spatial representation of envi- the southwest portion decrease over- cause of slopes exceeding 15%. The ronmental characteristics important all suitability in this small vineyard. ‘Roussanne’ blocks were rated slightly for the successful production of wine North-facing slopes result in low in- lower than the ‘Syrah’. A large block grape provides a holistic, efficient solation (mean of 1025 kW-h/m2). of ‘Roussanne’ was planted on alka- means for initial remote site evalua- Soil Survey Geographic data indi- line (pH 7.6 to 7.8), shallow soil tion. This type of DSS and analysis has catedrelativelyhighAWC(0.19to (mean of 36 cm) according to not been previously performed in the 0.20 cmÁcm–1), neutral soil pH, good SSURGO data. Vineyard 12 tied IPNW and should prove useful in as- drainage, and depths exceeding 200 cm. for the lowest MEMT (mean of sisting both new and existing growers Vineyard 10 recorded the second- –20.3 C), but had a much shorter with site evaluation and cultivar selec- most FFD of the ground truthing growing season (mean of 178 FFD) tion. It should also assist in spatially vineyards (mean of 213 d) and was compared with the Walla Walla Valley representative exploration of current tied for the third lowest MEMT (mean AVA ground truthing vineyards. and future wine grape production of –18.1 C). The site recorded VINEYARD 13. The viticulturist areas. Although this type of analysis 1557 CGDD. pointed out shallow soils featuring will never replace onsite assessments, it
96 • February 2014 24(1) can help focus prospectors’ attention South Africa. Geoscience Can. 30:161– capacity using a latitude-temperature in- on which site characteristics require 182. dex (LTI). Amer. J. Enol. Viticult. 39: 19–28. greater scrutiny. Beaudette, D.E. and A.T. O’Geen. 2009. In initial assessments, soil char- Quantifying the aspect effect: An applica- Jackson, R.S. 2008. Wine science princi- acteristics and topographically driven tion of solar radiation modeling for soil ples and applications. 3rd ed. Elsevier: climatic features generally corre- survey. Soil Sci. Soc. Amer. J. 73:1345– Academic Press, Burlington, MA. sponded to viticulturists’ perceptions. 1352. Jones, G.V. and A.A. Duff. 2007. The However, a lack of distinction in soil Daly, C., M. Halbleib, J.I. Smith, W.P. survey data made identification of climate and landscape potential for wine Gibson, M.K. Doggett, G.H. Taylor, J. production in the north Olympic Peninsula some problem areas more difficult Curtis, and P.P. Pasteris. 2008. Physio- region of Washington. Olympic Cellars, than others. One common discrep- graphically sensitive mapping of climato- Port Angeles, WA. ancy between viticulturist interviews logical temperature and precipitation and soil characteristic rankings was across the conterminous United States. Jones, G.V., A.A. Duff, and J.M. Myers. AWC. Areas with lower than ideal Intl. J. Climatol. 28:2031–2064. 2006. Modeling viticultural landscapes: AWC tended to fall into our ideal Davenport, J.R. and R.G. Stevens. 2006. A GIS analysis of the viticultural potential range suggesting our AWC ratings High soil moisture and low soil tempera- in the Rogue Valley of Oregon. Proc. may need to shift to give greater ture are associated with chlorosis occur- VIth Terroir Congr., Bordeaux and weight to higher AWC. rence in Concord grape. HortScience Montpellier, France, 3–7 July 2006: 256– This model focuses primarily on 41:418–422. 261. production characteristics necessary Ellis, E.A., P.K.R. Nair, P.E. Linehan, Jones, G.V., N. Snead, and P. Nelson. for wine grape. However, with the H.W. Beck, and C.A. Blanche. 2000. A 2004. Geology and wine 8. Modeling advancement of breeding programs GIS-based database management applica- viticultural landscapes: A GIS analysis of focusing on short-season and/or cold- tion for agroforestry planning and tree se- terroir potential in the Umpqua Valley of hardy wine grape cultivars in the lection. Comput. Electron. Agr. 27:41–55. Oregon. Geoscience Can. 31:167–178. United States, expansion of viticulture Evans, R.G. and A.S. Alshami. 2009. in the IPNW may reach beyond the June, C. 2000. Design of an intelligent Pulse jet orchard heater system develop- geographic information system for multi- currently described boundaries. Those ment: Part I. Design, construction, and locations falling in less-than-favorable criteria site analysis. J. Urban Regional optimization. Trans. Amer. Soc. Agr. Bio- Info. Systems Assn. 12:5–17. categories for FFD and GDD for wine systems Eng. 52:331–343. grape may prove to be ideal locations Jurisic, M., A. Stanisavljevic, and I. Plascak. for these new cultivars. Failla, O., L. Mariani, L. Brancadoro, R. 2010. Application of geographic informa- Minelli, A. Scienza, G. Murada, and S. tion system (GIS) in the selection of vine- The GIS tool described herein is Mancini. 2004. Spatial distribution of the first step of a DSS that allows solar radiation and its effects on vine yard sites in Croatia. Bulgarian J. Agr. Sci. users to evaluate sites by individual phenology and grape ripening in an alpine 16:235–242. components. From the identification environment. Amer. J. Enol. Viticult. Keller, M. 2010. The science of grape- of specific, potentially production- 55:128–138. vines: Anatomy and physiology. Elsevier: challenging site factors, onsite exam- Academic Press, Burlington, MA. ination may be conducted prioritizing Ferguson, J.C., J.M. Tarara, L.J. Mills, G.C. Grove, and M. Keller. 2011. Dy- those factors most easily and afford- Kurtural, S.K., I.E. Dami, and B.H. Taylor. namic thermal time model of cold hardi- 2007. Utilizing GIS technologies in selec- ably addressed with an idea of geo- ness for dormant grapevine buds. Ann. tion of suitable vineyard sites. Intl. J. Fruit graphic areas of greatest concern. Bot. (Lond.) 107:389–396. Use of this tool could help inform Sci. 6:87–107. Foss, C., D. Morris, N. Burnside, and N. decisions regarding cultivar selection, Meinert, L. and T. Curtin. 2005. Terroir wind machine placement, soil pH ad- Ravenscroft. 2010. FIBRE SERIES: Champagne comes to England: Assessing of the Finger Lakes of New York, p. 34–40. justments, drainage infrastructure, var- the potential of GIS in the identification In: M. Ebehart (ed.). Proc. 18th Keck Res. iable rate irrigation practices, ripping, of prime vineyard sites in south east Symp. Geol. Keck Geology Consortium, erosion control practices, and other England. 20 Nov. 2013.
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