Evaluation of Best Production Practices for Olive (Olea europaea) in Oregon. Part I

View the project final report

Commodities

• Fruits: olives

Practices

• Crop Production: cropping systems, varieties and cultivars, Cold hardiness, up-potting and winter protection for establishment
• Education and Training: extension, farmer to farmer, participatory research
• Production Systems: dryland farming

Olives are a high value specialty crop that continues to expand its cultivation in Oregon with some limitation, mainly due to winter climatic and environmental conditions that directly affect field establishment and plant survival. In the Pacific Northwest, low winter temperatures can negatively affect tree development during establishment, particularly during the planting year. Oregon growers are also facing a shorter growing season than traditional growing regions to ripen their fruit, in addition to a lack of scientific research-based knowledge of best production practices for the region. Production techniques to assist with orchard survival and possible cultivars that may be sufficiently resistant and produce quality fruit to adapt the crop to these conditions in Oregon’s shorter ripening season, must be identified. An additional important goal of the project is to reduce the cost of orchard establishment by providing information on propagation practices to facilitate local availability of adapted cultivars and for growers to be able to produce their own planting stock. Unfortunately, as most olives are produced in milder, traditional growing climates, comprehensive, peer reviewed and replicated relevant information on the production practices, propagation, and resistance to winter damage of olive cultivars does not exist for our region where winter temperatures are lower and growing seasons shorter. Our project is addressing these challenges by: a) obtaining multiple cultivars from multiple sources as cuttings or plants, rooting them, propagating them to experimental numbers, and evaluating them in a replicated, multi-year commercial field setting in Aurora OR (USDA hardiness zone 8b), and at the same time in a collaborative effort with growers that already have trees of different ages; b) replicated field trials at the North Willamette Research and Extension Center (NWREC) and Oregon State University Woodhall III Vineyard where potted nursery plants of commercial age of four cultivars currently grown in Oregon orchards will be both planted directly in the field, and also kept in protected structure over winter after transplanting to 3 and 6-gallon pots as they develop in size and age, to assess their respective susceptibility to freeze injury after field planting; and c) evaluating propagation season (by obtaining cuttings at different times in the year), rooting hormone (type and concentration), cultivar rooting ability, and growing substrates. As planned, the project has continued research and extension activities, but final outcomes have been delayed due to the global COVID pandemic. Once the data has been collected and analyzed for all three project components, final study results will be shared with industry and the public through multiple media forms and publications, as well as field days and presentations hosted in collaboration with the olive growers in Oregon. 

The main goals of the project are to assist in making olive production economically feasible and reduce climatic limitations (winter damage) during establishment of orchards for olive growers. In order to achieve these goals the specific project objectives include:

1. Determine most effective olive propagation techniques for Oregon by evaluating timing, rooting hormones, cultivar rooting ability, and propagation medium to successfully root potentially locally-adapted cultivars.
2. Establish the relative winter damage resistance (freezing cold hardiness) of olive cultivars through a multi-year field evaluation, to determine which are best adapted to our region and produce high-quality fruit in western Oregon.
3. Evaluate overwintering and up-potting practices to achieve rapid/successful orchard establishment and determine if plant size and maturity at time of planting influences subsequent cold hardiness as well as comparing planting location, season, and orchard floor management practices.
4. Conduct a comprehensive Oregon olive grower survey to determine grower needs and research priorities. Disseminate the information obtained via research and grower survey to industry stakeholders, existing and potential growers, project participants, and the general public via tours, visits, in-person communications, written media, social media, and classes, during and following the duration of the project.