It can be difficult to diagnose particular nutrient deficiencies/excesses in vines because various grapevine trunk diseases can sometimes display similar foliar symptoms. This is why it is very important to use soil and tissue analysis as tools in creating and fine-tuning vineyard nutrient management plans.
When collecting soil for analysis, first identify zones on your property where there are obvious variations in soil texture. This is often observed as differences in vine vigour. Sample these zones separately. A submitted sample should be a composite of about 10-20 sampling locations per zone.
With tissue analysis, whether petiole or leaf blades, it is best to sample various clone/rootstock combinations separately. Sample early in the morning when vines are under the least stress and ideally at defined phenological stages such as bloom and veraison. A submitted sample should consist of tissues collected from vines of similar vigour.
Although not specifically a Canadian resource, Washington State University extension has an excellent nutrition guide, “Vineyard Nutrient Management Guide in Washington State”.
TerraLink can assist through processing and recommendation of both tissue and soil tests. Our on-site Plant Science Lab at the Abbotsford location, processes tests quickly to get information to the grower fast in order to make decisions in real time.
Call 1-800-661-4559 for more information on lab services and agronomic recommendations.