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Juice Grapes

Grapesrandom-chlorosis-3Nitrogen rates and timing for Concord Grape Production
Concord grape requires  supplemental nitrogen fertilizer to produce a high quality crop and to sustain  long term production.  Nitrogen  fertilizer application rates in Central Washington  have been developed largely by grower experience.  Recent research looking at nutrient  partitioning in whole Concord  vines indicates that lower rates of fertilizer, timed to meet phenological  stages of high demand, could increase N use efficiency, reduce potential for  off target N movement, and maintain or improve productivity.

Given recent drought years and  water limitations, some Concord  growers are turning from furrow and sprinkler irrigated systems to drip irrigation.  Metered introduction of  nitrogen into drip irrigation systems across  several timings is a cost effective fertilizer application method. In addition,  high labor costs and level or declining returns are resulting in more  mechanical and minimally pruned Concord  vineyards to help reduce costs.

The specific objective of this  project is to compare the effect of nitrogen fertilizer application rates and  timing on grape tissue nitrogen concentration, yield, quality, and canopy size  in a minimally pruned Concord  vineyard.

Micronutrient  Supplements for Concord Grape
Micronutrients have a limited  availability in the high pH soils in central WA that are used for Concord grape  production.  As a result, many growers  use micronutrient supplements to assure adequate availability.  Recent research on mineral partitioning in whole  Concord vines indicated a seasonal need for <  1 lb/A of Zn, B, and Cu, but the time of need and tissue destination differ by  nutrient (Davenport  and Pradubsuk, unpublished data).  Iron  is also of great interest to growers due to the regular occurrence of  chlorosis.  Method and timing of application  is a frequently asked question in micronutrient management.

The specific objectives of this  project are:
1.  To compare rates of B, Cu, and Zn supplements  on yield, brix, and tissue nutrient concentration.
2.  To compare soil applied granular vs. liquid  applied foliar B, Cu, and Zn supplements on yield, brix, and tissue nutrient  concentration.