Improving Orchard Management through Multi-Species Cover Crop Mo

View the project final report

• 2015 annual report

Commodities

• Fruits: cherries, general tree fruits

Practices

• Crop Production: cover crops, crop rotation, nutrient cycling
• Education and Training: farmer to farmer
• Pest Management: biological control
• Production Systems: holistic management, organic agriculture, permaculture
• Soil Management: green manures, organic matter, soil analysis, nutrient mineralization, soil chemistry, soil microbiology, soil physics, soil quality/health

This three-year project has three primary objectives: to research and quantify some of the key benefits of multi-species cover crop mixes in orchard systems, identify the best seed mixes for regional soils and climate, and demonstrate management techniques that orchardists in the region can use to effectively incorporate cover crops into their operations. Currently, conventional management of the orchard floor in the Pacific Northwest involves using herbicides to keep a bare strip of soil directly under the tree rows and maintaining a perennial grass sod alleyway between the tree rows. The grass sod, predominantly creeping red fescue, does a good job of preventing soil erosion but provides few of the other benefits cover crops offer. The sod root systems are shallow, they do not scavenge effectively for nutrients, they do not increase soil microbial life beneficial to tree health, nor do they provide nectar or pollen to beneficial insects. Planting cover crops in the alleyways could increase the sustainability of tree fruit orchards, but this practice is not utilized at all in the Columbia Gorge region, according to the local Oregon State University Extension office. Multi-species cover crop ”cocktails” of five species or more have been utilized more extensively in annual cropping systems and have been shown to improve soils and crop yields in ways that researchers still do not fully understand (http://organicfarms.wsu.edu/blog/cover-crop-cocktail/). Although it is not within the scope of this small project to understand all of the mechanisms at play with respect to cover cropping benefits, the project team will try to identify the best cover crop mixes for the region and try to understand how they impact fruit quality and economic return of the fruit crop. The objectives describe how they will evaluate the cover crops to make that decision. If cover cropping results are positive, this should lead to increased adoption of this practice by orchardists in the region and increased sustainability of this cropping system. The project team, led by cherry orchardist Mike Omeg and Technical Advisor Lynn Long (OSU Extension), along with collaborators from the Wasco County Soil & Water Conservation District and USDA NRCS, expect to see cover cropping benefits in reducing soil compaction rates and increasing tree nutrient uptake, fruit size, and fruit quality, among others. Cover crop success is site dependent and often evolves through trial and error. Because cover crop species and management practices may have simultaneous benefits and disadvantages, the best choice is often a compromise. Single year results do not provide an adequate evaluation of a cover crop’s potential (UC Davis Publication 3338). That is why multiple year experiments, such as this one, are important to find out what works best with a given farm, its microclimate, soils, set of equipment, and other factors. In the case of long-term perennial crops such as fruit trees, benefits of the cover crops may take several years to become apparent. For this project, education and outreach will include two field days (pre- and post-harvest), a cover crop in orchards “How-To” guide that will be distributed for free to orchardists in the region, articles in trade publications, and sharing the research results via social media outlets. The project will take place on a 6.5-acre mature cherry block (Regina variety) that is leased by Mike Omeg of Omeg Family Orchards in The Dalles, Oregon. Eighteen ½ acre alleyway treatments will be planted to cover crop mixes with multiple data points collected throughout their growing cycle. This particular block of cherry trees was selected due to uniformity of tree age (six years), variety (all Regina), rootstock (all Gisela rootstock), uniform growth and vigor throughout the block, consistent soils (mostly Chenowith loam), consistent irrigation system, and no disease or pest “hotspots.” Also, the layout of these trees allows for the treatments to be set up in a uniform grid pattern. This allows for more efficient plot management and monitoring. There is also good vehicle access, plenty of parking, and is near a main roadway for educational field days.

Objectives:

1. To research how planting times, seeding rates, and seeding equipment affects multi-species cover crop establishment (Years 1-3)

2. To research three different cover crop mixes of two species or more on the following parameters: soil compaction, tree nutrient uptake, fruit size and firmness, and fruit yield (Years 1-3)

3. To quantify economics of cover crops, including the following parameters: cost of seed, cost of establishment, nutrient contributions, pest and disease hotspots, management costs, fruit yield and quality (data collected in Years 1-3, results published in Year 3)

4. To encourage the adoption of multi-species cover crop mixes amongst commercial orchardists in the region and beyond (Years 2 and 3)

5. To quantify the adoption impacts of this project via evaluation techniques, such as before-and-after questionnaires, follow-up surveys, and site visits (Years 2 and 3)