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Wine Grapes

Winegrape  Nutrition: Deficiency Symptoms and Micronutrient Response
Atypical visual symptoms are the first indicator of vineyard  production problems.  Nutritional  deficiencies often appear as leaf discoloration, but can also appear as  misshapen clusters, fruit, or discoloration of other tissues.  As an added complexity, insect damage can  often mimic certain nutrient deficiency symptoms.  Deployment of the appropriate corrective  measures is dependent on identifying the cause of the symptoms. However there  are few published resources which aid in visual assessment of nutrient  deficiencies.

Potted-Wine-grapesWork to develop low end critical nutrient standards has been  based on either field trials with specific nutrient levels or on tissue survey  projects.  As a result, the absolute low  end of nutrient concentration in wine grape petioles and leaves is not based on  induced deficiencies and may not fully represent truly deficient  conditions.  With this project, we  propose to establish these low end levels under controlled conditions and will  analyze all tissues to determine if fruit vs. leaf (blade or petiole) vs. some  other tissue type would best reflect the status of a particular nutrient.  In addition, this effort will produce visual  guidelines for the evaluation of nutrient deficiency symptoms.

 

Can  late season foliar nitrogen application reduce wine grape nitrogen nutrition stress?
Nitrogen (N) management is critical to  successful grape production.  When nitrogen is added to a vine with low  nitrogen nutrition, nitrogen metabolism is stimulated causing an increase in  protein synthesis.  Based on recent whole plant nutritional analysis of grapevines in the Pacific Northwest, N is less  available at a time when it is essential for fruit growth and development, and  to build storage reserves for the following growing season.  Research has  also indicated that soil applications of N at veraison do not move to the  appropriate organs for fruit development, thus these applications increase the  risk of N leaching throughout the wet, winter months.  This field  experiment is being conducted using own-rooted Merlot and Riesling grapevines (Vitis  vinifera L.).  Twelve plots were designed in a four block pattern with  each row serving as a block.  Plots were replicated at each  site.  This two year study involves using a 6% solution of  liquid urea applied at weekly intervals beginning at veraison, for five total  applications (total of 6.8 kg N / ha).  For the organic nitrogen a single  rate of Biolink Vegan Nitrogen (6-0-0) was applied at the same rate for the  same duration of time.  The objective is to determine the effects of late  season foliar N applications with both conventional and organic N sources on  yield, yield components and vegetative growth in irrigated vineyards of Eastern Washington.

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Developing a Site Selection GIS for Inland Pacific NW Grape  Production
Absolutely quantifying terroir will likely never  be possible. However, by scrutinizing major factors influencing grape vine growth, we can delineate areas for grape production ranging from suitable to  ideal.

By compiling and analyzing climatic, topographic, soil and land use  geospatial data in a geographic information system, we intend to develop a site  selection model for grapes in the inland Pacific Northwest.  Washington state is currently second only to California in wine grape production in the Catherine_vinesUnited States  and it leads the nation in Concord grape production. The goal is to provide  grape growers with recommendations of species and varieties in order to  optimize the potential of the site and help push the region’s grape production  toward continued success and excellence.