Initial Project Summary
Project objectives
- Characterize soil moisture conditions throughout the season among different soil types common to Willamette Valley wine grape production.
- Determine vine water status, growth, and berry development response to weather and soil moisture conditions throughout the season among different soil types.
Importance to the Oregon wine community
Most Oregon vineyard businesses do not have budgets to support soil moisture and plant water stress monitoring and often are making best-guess estimates on when to initiate irrigation or vineyard floor management practices that influence soil moisture. This project will generate regionally-specific information about soil water content, climatic conditions, and the impacts of these factors on vine growth that will aid others (e.g., growers, management companies, consultants) to determine best management practices.
This work is being conducted in collaboration with Dr. Paul Schreiner, research plant physiologist, USDA-ARS, and Andy Gallagher, Red Hills Soils. In addition to the OWB grant, support was provided by the Erath Family Foundation for soil moisture sensors and equipment. Fruit Growers Lab, Inc. donated tissue nutrient analysis services.
Progress Reports
2019-20: Year 1 Update
In its 2019-20 fiscal year, the Oregon Wine Board of Directors granted $417,000 to researchers for nine projects with the potential to advance quality grape growing and winemaking in Oregon. The update below is part of a series to let you know about the status of these projects.
Progress so far:
The project is located in a commercial Pinot noir vineyard in Newberg, OR. Data collection was initiated in January 2020 with soil moisture sensors installed under the vine row and the middle of the alley between vine rows at a depth of 18 inches and 36 inches from the soil surface. Sensors were placed in two blocks within each of three soil types, and a weather station was installed in February 2020 to begin on-site climate monitoring. Data has been downloaded monthly, and phenology advancement and vine growth data have been collected this season, including timing of bud break, bloom, shoot growth rates, and sampling for vine nutrient analysis.
Next steps:
We will continue monitoring soil moisture and environmental data and taking measurements on vine growth and fruit development through 2022. Results of the study will be summarized and compared with other soil moisture monitoring efforts in other Willamette Valley research blocks and with the local technical group to determine how the research compares with other vineyards in the region. This work will lead to future research on the soil moisture impacts of vineyard floor practices.
2020-21: Year 2 Update
In its 2020-21 fiscal year, the Oregon Wine Board of Directors granted $350,000 to researchers for eight projects with the potential to advance quality grape growing and winemaking in Oregon. The update below is part of a series to let industry members know about the status of these projects.
Progress so far:
Soil moisture, weather data, and vine growth responses were measured in 2020 in a Pinot noir vineyard that had vines of the same age, clone, and rootstock growing on three soil types, including Saum (volcanic), Dupee (sedimentary), and Willamette-Woodburn (marine sediments). Sensors measured soil moisture, soil temperature, and electrical conductivity at two monitoring locations per soil type to a depth of 18 and 36 inches under vine and in the middle of the alley between rows.
Soil moisture remained relatively consistent through spring, with soil moisture decline starting mid-June, shortly after bloom, and continuing through summer. Soil moisture decline was greatest at the 18” depth. Willamette-Woodburn soil had the greatest decline in soil moisture yet the largest vine size (based on dormant pruning weight), suggesting that the higher-vigor vines in that soil type required more water from the soil profile than vines in the other two soils.
There were no clear differences in vine water stress of the three soil types. Berry weight lagged slightly for vines in Willamette-Woodburn, but there were no differences in the berry development curve. By harvest, yields were similar from each soil type. However, the Willamette-Woodburn had lower Brix and sugar per berry compared to the other two soils. Willamette-Woodburn vines also had greater tissue N at véraison and berry YAN at harvest compared to vines in the other two soils. Since the site was not irrigated and no fertilizers added, the differences in growth and berry composition reflect differences in soil fertility and moisture.
Next steps:
We will continue to this project through the 2021 and 2022 growing seasons. Results of the study will be summarized and compared with other soil moisture monitoring efforts in other Willamette Valley research blocks and with the local technical group to determine how the research compares with other vineyards in the region. We will develop future research projects that will build upon foundational knowledge gained from this study (e.g., timing and type of vineyard floor practices).
Primary support for this project is provided by the Oregon Wine Board grant. Additional support was provided by the Erath Family Foundation for soil moisture sensors and equipment. Fruit Growers Lab, Inc. donated tissue nutrient analysis services.
2021-22: Year 3 Update
In its 2021-22 fiscal year, the Oregon Wine Board of Directors granted $289,000 to researchers for six projects with the potential to advance quality grape growing and winemaking in Oregon. The update below is part of a series to let industry members know about the status of these projects.
Progress so far:
Soil moisture, weather data, and vine growth responses were measured since 2020 in a Pinot noir vineyard that had vines of the same age, clone, and rootstock growing on three soil types, including Saum (volcanic), Dupee (sedimentary), and Willamette Woodburn (glacial deposits). Sensors measured soil moisture, soil temperature, and electrical conductivity at two monitoring locations per soil type to a depth of 18 and 36 inches under-vine and in the middle of the alley between rows. Soil water content was at field capacity (full soil profile) from winter through most of spring, with the start of soil moisture decline in mid-June or early July, depending on year, and continued through summer. Soil moisture decline was greatest at the 18” depth while the 36” depth remained at more moist soil conditions much of the season. Willamette-Woodburn soil had the greatest decline in soil moisture yet the largest vine size (based on dormant pruning weight), suggesting that the higher vigor vines in that soil type required more water from the soil profile than vines in the other two soils with potentially more extensive root systems. The 2021 data showed that the vines in Woodburn-Willamette had less water stress during summer than vines growing in Dupee, which is also evidenced by the larger vine size. By harvest, yields were higher in Woodburn-Willamette vines compared to the other two soil types in 2021 only. Willamette-Woodburn vines had greater tissue N at véraison and berry YAN at harvest compared to vines in the other two soils. Since the site was not irrigated and no fertilizers added, the differences in growth and berry composition reflect differences in soil fertility and moisture. Furthermore, these two years suggest that vines may respond to vineyard floor practices or soil conservation methods in the Dupee or Saum soil, but they are not necessary in the Woodburn-Willamette soil.
Next steps:
We will continue to this project through the 2022 growing season. Results of the study will be summarized and compared with other soil moisture monitoring efforts in other Willamette Valley research blocks and with the local technical group to determine how the research compares with other vineyards in the region. We will develop future research projects that will build upon foundational knowledge gained from this study (e.g., timing and type of vineyard floor practices).
2023: Final Report
Final Summary
Soil moisture, weather data, and vine growth were measured during three growing seasons (2020-2022) in one vineyard with three soil types. Pinot noir of the same rootstock and vine age were grown in three soil types, including sedimentary soils (Dupee), volcanic soils (Saum), and glacial flood deposit soils (Woodburn-Willamette).
Soil probes measured volumetric water content, soil temperature, and electrical conductivity at depths of 18- and 36-inches under vine and in the middle of the alley between vine rows. Soil monitoring was continuous from Jan. 2020 to Dec. 2022. Coming into each growing season, soil moisture was at field capacity and remained relatively consistent through much of spring each year. However, the start of soil moisture decline varied each year depending on rainfall patterns. Soil moisture decline began in mid-June 2020, in early to mid-April 2021, and in mid-June 2022. There was a gradual soil moisture decline throughout summer each year when there was little to no precipitation. All years had similar annual and seasonal precipitation, although the timing of rainfall varied, with the driest spring in 2021 and the wettest in 2022. Soil moisture was reduced more at the 18” depth than at the 36” depth, and the lowest soil moisture was recorded in Woodburn-Willamette (sedimentary soil) for all three years. Vines grown in Woodburn-Willamette soil had the greatest vegetative growth and fruit yield for all three years compared to Dupee and Saum, both of which had similar vine vegetative growth and yield.
Interestingly, the largest vines and greenest canopies were in the Woodburn-Willamette soil that had the lowest soil moisture, suggesting that the higher-vigor vines may have required more water from the soil profile, than in the other two soil types at the depth measured. Evaluation of the soil profile in Dec. 2022 revealed that Woodburn-Willamette had a deeper soil profile, allowing for rooting below 36” and access to greater soil volume and soil moisture at depths below where our sensors were placed. Leaf water potential and leaf gas exchange measures further indicated that Woodburn-Willamette vines were under less stress than Saum and Dupee. Despite variable vine water status, berries of vines in each soil type reached commercially acceptable ripeness each year. Saum consistently had the most advanced berry ripeness with the highest total soluble solids and pH and the lowest titratable acidity, potentially due to a more rapid phenological development. However, Dupee had the greatest sugar/ berry, likely due to its higher level of sustained water stress. Findings from this three-year study show that soil type plays a pivotal role in water availability, plant growth, yield, and fruit chemistry. This highlights the importance of understanding site-specific characteristics and creating a management program that is more tailored to the individual vineyard soil characteristics.
Download Complete Report
Download the Research Project PowerPoint
Watch 2022 Oregon Wine Symposium Research Report
Watch 2023 Oregon Wine Symposium Research Update
Dr. Patty Skinkis conducts applied research and as an Extension Specialist, Patty develops educational programs and informational publications for the Oregon wine and grape industry. Her research focuses on applied viticulture and whole plant physiology to understand causes and manage vine vigor/vine balance, and impacts on fruit composition and wine quality. Her research also includes work on yield (from bud fruitfulness to crop thinning), canopy management, sustainable viticulture, and understanding factors that drive industry production decision-making. Her outreach efforts include bringing industry and academics together in technical groups to foster information exchange. She also teaches viticulture at Oregon State University. Her efforts expand beyond Oregon, as she is a member of the National Clean Plant Network – Grapes Advisory Board, is an associated editor for the American Journal of Enology and Viticulture, and served as a board member and held leadership positions in the American Society for Enology and Viticulture.
