Identifying Optimal Nutrient Concentrations For Premium Winegrape Production Based On Physiological Needs And Fruit Quality.

Authors: Schreiner, Roger - Paul

Submitted to: Northwest Center for Small Fruit Research Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 4/24/2006
Publication Date: 11/12/2006
Citation: Schreiner, R.P. 2006. Identifying Optimal Nutrient Concentrations For Premium Winegrape Production Based On Physiological Needs And Fruit Quality. Northwest Center for Small Fruit Research Proceedings. CDROM.

Interpretive Summary:

Technical Abstract: Self-rooted Pinot noir (clone UCD2A, Pommard) vines were grown in a coarse, sand medium in a pot-n-pot system supplied with complete mineral nutrient solution for 3 years (2003-2005). Beginning in May 2006, different nutrient treatments (4 levels of each N, P or K with all nutrients held constant) were applied to vines by fertigating 1-3 times per week. Shoot growth of Pinot noir, leaf N concentrations, and leaf SPAD readings were reduced by the low N treatments, but not by the low P or low K treatments. Nutrient treatments did not affect chlorophyll fluorescence, stomatal conductance or soil moisture on any given sampling dates in 2006. Unfortunately, a high level of inflorescence necrosis (IN) occurred in this vineyard at the end of the bloom period in 2006. Because IN was both highly variable from vine to vine and affected by nutrient treatment (IN was significantly reduced in the two lowest N treatments), we chose to remove all clusters from experimental vines to preserve uniformity and start over again next year. Even though IN was reduced by the lowest N treatments in these vines, the high level of IN observed this year was probably a result of waterlogged conditions that occurred over the winter as opposed to the application of too much N in our fertilizer, because leaf N concentrations of these vines at bloom and veraison were actually lower than typically found in Oregon vineyards. Roots in some pots had blocked the drain holes resulting in waterlogged (anoxic) conditions over the winter. All pots were retrofitted with copper screen (to inhibit root growth on pot bottoms) in March 2006, which was successful in inhibiting roots from growing on the bottom of pots (examined in October, 2006).