Nitrogen 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 1 lb/A of Zn, B, and Cu, but the time of need and tissue destination differ by nutrient (Davenport and Pradubsuk, unpublished data).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.