Good Fruit Grower

April 15

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photo by melissa hansen Michelle Moyer demonstrates how WSU's vineyard site evaluation computer model works. But it's not ready for public use and is currently used only internally by WSU research and extension staff. Also, the model is set up to work in vineyards of commercial size—not small acreage parcels. During field testing, the model was able to accurately assess in-season conditions that would be favorable or detrimental to grape production, such as heat accumulation and frost-free days. The model also provided excellent insight into site soil conditions and situations such as excess or insufficient drainage. But a major limitation is that it can't capture extreme weather events. "The model in its current form is not able to predict the likelihood of dormant freezing events, a critical factor in site selection in eastern Washington," she stated in a report. "An additional data layer that would include the likelihood of dormant season low-temperature events is necessary to improve the model's prediction of 'no-grow' sites." She also noted that some of the raw data is not detailed or current enough, and therefore is limited in value. For example, most of the soil surveys were conducted by the government decades ago and have not been updated. If the site has been farmed since the soil survey, soil amendments could have altered the soil pH or installation of tile drains could have changed drainage issues, for example. Additionally, resolution of the topography maps is not high enough to provide adequate slope or air drainage information. And, the model does not factor in water availability or legal water rights, a key ingredient to grape growing. Although the model itself didn't turn out as originally envisioned, she says the database has proven to be a very useful tool for WSU Extension to use for off-location evaluation. Evaluation not selection She stressed that the model should be considered a site "evaluation" tool and not a site "selection" tool. One of the early goals of the model was to be able to identify sites capable of producing "ultra premium" wine grapes. "But people are not part of the model's site evaluation," she said. "There are two things you can't model— you can't model the vineyard manager or the winemaker." To prove her point, she modeled a vineyard site in the state known for producing perfect or very high scoring wines. The computer gave the site a moderate score for vineyard appropriateness. "Great vineyards are about the people," she said, adding that a good vineyard manager can make any site work, while a poor manager can make a good site not work. "Agriculture is about risk," said Moyer. "This model helps me pinpoint potential problems and challenges that a grower will encounter on a given site. It helps me direct the grower toward things he or she should be concerned about and is a way to help growers take ownership of the risks and make informed decisions." • Introducing . . . TM Certified Organic & Kosher crop aid that reduces sources of food to pests and bacteria PREHARVEST PROGRAM treats • fire blight • mildew • scab • gummosis • codling moth • woolly aphid Also, increases sugar Brix in leaves & fruit. POST-HARVEST PROGRAM reduces • decay and rot in storage • ethylene production Vericet Improves Fruit Set Through . . . Increased Rate and Accuracy of Pollen Tube Growth Increased Health and Receptivity of the Flower Increased Pollinating Insect Activity TM To learn more about our latest pollination enhancement visit our web site or call today: 209-595-2056 or 209-595-3031 Tree Wash is not a pesticide. For more information, please call us or visit our Web site. POLLEN CONTROL Roger & Sally Ellis Organic Farms LLC Modesto, CA Rober Ellis (509) 945-1718 Jim Davis (509) 945-2946 GOOD FRUIT GROWER April 15, 2013 35

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