Location: Horticultural Crops Production and Genetic Improvement Research Unit
Project Number: 2072-21000-055-036-G
Project Type: Grant
Start Date: May 1, 2022
End Date: Oct 31, 2024
Objective:
1. Evaluate long-term, multi-site yield management data for cluster-thinning and vineyard characteristic impacts on vine productivity, fruit composition, and wine quality.
2. Determine changes in industry yield management practices and their impact on vineyard and winery economics.
3. Develop models that forecast climate change impacts on yield, fruit composition, and wine quality.
Approach:
A 10-year data set from the Statewide Crop Load Project (SCLP) will be used for statistical analysis of cluster thinning and vineyard site impacts for Objective 1 and to develop climate econometric models for projected climate change in Objective 3. The data set includes fruitfulness, yield components, yield, vine tissue nutrients, pruning weights, site characteristics, and fruit composition data from 16 commercial Pinot noir vineyards from 2012-2021.
Objective 1 will include statistical modeling of the data. Linear mixed effects regression models will be fit for measures of vine productivity, fruit composition, and wine quality, with experimental factors and observational vineyard factors treated as fixed effects and vineyard and year treated as random effects. This model class is flexible enough to handle unbalanced data resulting from different vineyards, differing numbers of years, and missing measurements. Where appropriate, model selection will be performed using likelihood ratio tests, and all models will be assessed for goodness of fit using standard diagnostic procedures. Final models will be used to identify specific yield ranges where target production metrics are met, how this relates to vineyard-specific measurements, and how it varies across vineyards and years.
Objective 2 will include a systematic evaluation of industry yield management practices. Oregon producers will be solicited for information through an online survey. This survey will gather information on current and past yield management practices, production costs, and economic impacts. A subset of respondents will be selected for phone/online interviews to obtain detailed information. Individuals selected will reflect different producer roles, tiers of production, and location. Simultaneously, the industry collaborators in the SCLP will complete an online survey to determine what they observed, learned, and implemented. Follow-up interviews will be conducted with key producers for in-depth data about observations, adaptations, and economic impacts. Production economic data from surveys and interviews will be used in Objective 3.
Objective 3 will assess how yield and wine quality will be impacted by changes in temperatures and precipitation by using standard economic production models that link to climate change models. Data from the SCLP will be used to identify specific field-level impacts on yield using vine size, nutrient, and fruit composition variables with a variety of controls to deal with unobserved heterogeneity. Additional data may be obtained from USDA NASS that provides county-level yield estimates for longer time-series of data. We will then link temperature and precipitation data gathered from PRISM to the spatial grid of the project vineyards located in the Willamette Valley. Predictions of climate impacts will then be estimated using CMIP6 climate multi-model ensembles that provide spatial resolutions of climate impacts throughout the world from present to the year 2100. The model will be used to inform long-run projections of yield as a result of climate change and to develop spatial maps that highlight changes in the Willamette Valley.
