Documenting Symptoms and Critical Values for Nutrient Deficiencies in Wine Grapes

In 2008, 150 Cabernet Sauvignon and 150 Semillion grape plants were planted in pots in sand culture. During the intervening winters these were stored in cold storage, pruned to 3 buds in the spring, and from the summer of 2009 - 2011 were treated by either providing a complete nutrient solution (30 reps per variety) or a solution lacking 1 essential nutrient (10 reps per variety/nutrient). During 2010 and 2011, each plant was photographed weekly using a black background for contrast. At the end of 2010, three replicates per variety and deficiency were harvested as whole plants, roots were washed, plants were separated into different organs, and organs were analyzed for nutrient content. This was repeated post bloom in 2011 with the remaining plants at the end of the 2011 growing season.

In year 1 the vines were planted in the spring and allowed to establish. They were pruned to uniform above-ground plant mass, overwintered in controlled cold conditions, and removed in the spring to begin the new growth cycle. Nutrients were supplied during the second season using modified Hoagland's solutions. With 4 plants of each variety, one nutrient was withheld to establish deficiencies of nitrogen, phosphorous, potassium, calcium, magnesium, sulfur, zinc, boron, iron, copper, manganese, and chloride.

Objective 1: Plants will be visually evaluated for deficiency symptoms on foliage, fruit, wood, and, if appropriate, roots. A photographic document of the symptoms will be made. Each plant was photographed weekly to develop a photo record of the symptoms as they develop. It appears that there are significant differences between red and white grape cultivars.

Objective 2: Upon completion of Objective 1, the vines will be destructively harvested and separated into different components: foliage (leaves, petioles), wood, fruit (berries, rachis), and roots. Tissues will be dried and analyzed for the suite of nutrients listed in Objective 1. Analysis for N and C will be conducted using dry combustion "in-house" at WSU-Prosser. A duplicate set of tissue samples will be sent to a commercial test lab for analysis of the other nutrients by Inductively Coupled Plasma (ICP) Spectroscopy, which does not include N or C in the suite of nutrients it evaluates. The commercial test lab is the most cost effective and has routinely provided research quality data.