The goal of optimizing grapevine nutrition is to improve vineyard productivity, sustainability, product quality, and vineyard profitability. The market demands for grapes drive grower decision-making in the vineyard. Raisin and juice grape growers aim to maximize yields, table grape producers need to maximize yield and fruit appearance, and wine grape growers prioritize berry quality parameters that influence wine composition often at the expense of yield. The environment affects vine growth and thus nutrient demand, so nutrient standards are not universal across vineyards in different regions or different grape markets.
The Plant Nutrition Team’s goal is to determine standards for grapevine nutrition levels appropriate for different varieties, markets, production goals, and environments. Understanding how different plant tissues respond to nutrient inputs and correspond to specific production goals will help develop these standards. The team includes researchers from Washington, Oregon, California, and Virginia.
To develop nutrient standards, the team is conducting vineyard trials in all four states represented by the research team. These trials evaluate vine responses to specific nutrients of regional concern to growers. Field-based research trials are being conducted to evaluate responses to variable nutrient levels through different rates of fertilizer inputs. This team works with the Sensor Development Team to test the ability of sensors to determine actual tissue nutrient levels. The team also works with the Product Quality Team to determine the influence of different nutrient levels on fruit and wine composition.
Below are the trials being conducted in each state.
- Washington: Field trials were conducted in commercial Syrah, Chardonnay, Sauvignon blanc, and Concord vineyards to evaluate different nitrogen and potassium fertilizer rates. The team tested different tissue sampling strategies, and the Sensor Development Team took images of vines in the different treatments to test how their sensor output correlates with tissue nutrient levels. At harvest time some of the experimental plots were processed into wine tested for chemical composition and in a sensory evaluation by the Product Quality Team.
- Oregon: Nutrition experiments were conducted in three commercial vineyards, focusing on nitrogen in Chardonnay and potassium or magnesium in Pinot noir. Fruit from the nitrogen trial was provided to the WSU Product Quality Team to produce wine, and analyze wine composition and sensory properties. Sensor ground-truthing was conducted in 2022 and 2023 by the WSU Sensor Development Team.
- California: Nutrient trials were conducted in field grown vines and potted vines for raisin and table grapes. Nutrient treatments consisted of nitrogen and magnesium application rates. Multispectral imaging is being evaluated within multiple vineyards.
- Virginia: Field trials were conducted using both soil and foliar nitrogen application in Chardonnay and Chardonel vineyards. The berries were sampled at harvest for yeast assimilable nitrogen (YAN) and basic fruit chemistry. Wines were produced by the Virginia Tech Product Quality Team, with focus on YAN and sensory results.
Team members
Researchers (see details here)
- Markus Keller, Washington State University
- Paul Schreiner, formerly with USDA-ARS
- Matthew Fidelibus, University of California-Davis
- Drew Harner, Virginia Tech
Research Lab Staff
Pierre Davadant, PhD student, Washington State University
Pierre is studying grapevine physiology under the supervision of Dr. Markus Keller. He has a background in agriculture, viticulture, enology and teaching. Pierre is focusing on nitrogen fertilization and studies the impact of foliar-applied and soil-applied nitrogen on grape composition
Santosh Kalauni, MS student, Oregon State University
Santosh worked with Dr. Paul Schreiner’s lab at the USDA-ARS Horticultural Crops Research Unit in Corvallis, OR on experiments to determine the effect of nutrient applications (N, K and Mg) on vine nutrient status, productivity, and fruit quality in Oregon vineyards. He is examining nutrient sufficiency thresholds for various tissues based on vine productivity and quality parameters.
Nataliya Shcherbatyuk, Postdoctoral Researcher, Washington State University.
Dr. Nataliya Shcherbatyuk was a postdoctoral researcher in Dr. Markus Keller’s lab. Her focus was on re-evaluating and optimizing sampling protocols and determining how rapidly vines respond to nutrient adjustments. The main goal of her work was to improve tissue sampling protocols and enhance management practices for spatially heterogeneous vineyards. She now works on project management and outreach but continues to work with the Keller on outcomes.
Dana Acimovic, Research Associate, Virginia Tech
Dana conducted two field studies in collaboration with commercial vineyards in Virginia. The research goals were to understand nutrient levels, in particular nitrogen, necessary for the optimal vine growth and to develop new protocols for plant tissue nutrient analysis. Collected data serves the engineering team on the project to build ground-truthing sensors. Grapes from the studies were made into wine by Amanda Stewart’s Lab at Virginia Tech to investigate the effects of nitrogen fertilizer on yeast-assimilable forms of nitrogen during fermentation and wine quality.
