Pruning weight reflects vine capacity in the Big Dig

Today’s Concord picture of the day is from the “Big Dig” vine excavation study from 2003. Mature Concord vines were manually excavated, roots and all, at 10 different time points throughout the growing season. Then the vines were separated by fine roots, thick roots, trunks, cordons, canes, shoots, leaves, and fruit and analyzed for dry matter, nutrients, and carbohydrates.

There are a lot of interesting lessons from the big dig but one of the more practical observations was about the use of vine pruning weight to predict total vine production. Viticulturists often talk about measuring the mass of one-year-old dormant cane prunings to assess “vine size.” It is usually referred to as measurement of last season’s canopy growth and a predictor of next season’s yield potential. The assumption is that pruning weight is also reflective of the vine’s total growth capacity, which means ALL the annual vegetative and fruit growth. This is rarely measured in mature vineyards because nobody wants to dig out the entire root mass of an established vineyard…which we did in the Big Dig…with pitchforks…It was fun…I highly recommend it. Lo and behold, when we compared the cane dry mass to the dry mass of the entire vine – roots and all – there was a positive linear relationship. This reinforces the usefulness of vine pruning weight in determining Concord growth potential. We believe vine size is such a useful tool in Concord vineyard management that we are now using sensors to spatially measure vineyard pruning mass.