Cover Cropping in Okanagan Orchards
Field Day Recap | October 2024
In fruit orchards across the Okanagan, growers and researchers in the BC Living Lab are testing a big question: How to grow cover crops that help mitigate climate change and support orchard production goals, without compromising crop health? At an October field day in Lake Country, growers and AAFC Summerland researchers braved the rain to share the successes and challenges of their collaborative research trials, and demonstrated no-till seeding in apple orchard drive-rows.
Maximize Goals, Minimize Harm
New and seasoned Okanagan fruit growers are expressing a multitude of interests in planting cover crops in drive-rows and/or crop-rows. Suggested benefits for resilience range from reducing weed pressure and fertilizer use to storing more carbon in the soil, or protecting crops from sunlight reflectance. Some growers are also experimenting with mow-and-blow mulching, while others see potential in cover crops to support biodiversity or rotational grazing. No matter the growers’ goals, project collaborators cautioned that finding the right varieties and approach takes intention, calculation of risk, and experimentation:
- Choose varieties with care; some can host pests that pose risks to orchard health: Some broadleaf cover crop species like clovers can host undesirable pests and diseases, like the leafhopper vector and pathogen associated with little cherry disease.
- A lot can be learned from cover cropping approaches in vineyards or other tree fruits, but not everything: As suggested for local vineyards, a legume-grass cover crop mix is a good start, but varieties quickly change with production goals. A cherry grower selected fast-decomposing legumes for soil organic matter and lower nitrogen fertilizer needs, while an apple grower chose species that didn’t break down to have more control over nitrogen’s impact on fruit quality.
In-Field Insights
During a seeding demonstration, a vineyard-sized no-till seeder planted a cover crop mix tailored to the growers’ goals for their orchard. Using a dry hopper, similar-sized seeds, and calibrating drill depth were factors that led to successful seeding. By seeding in the fall, researchers expect more root than top growth, which increases soil carbon stores – a climate mitigation goal of the program.
Growing Pains, Getting Established
- Different seed sizes in a mix can require multiple planting approaches—appropriate seeding density, distribution and depth are important for crop performance.
- Equipment may not be available—a no-till seed drill with dimensions that fit an alleyway safely are costly and not yet widespread, but custom seeders from vineyards are helping.
- Integration with harvest and other production activities—the project is prioritizing varieties that can tolerate traffic, but weather variability can mean spring-seeded cover crops may still be delicate.
What’s Up Next?
The BC Living Lab’s collaborative approach emphasizes the value of trialing, observing, and adapting practices to fit each farm’s goals and conditions. While working with growers to trial feasibility on active farms, researchers are continuing to assess how cover crops contribute to storing carbon in the soil and reducing greenhouse gas emissions. Investigating drought-tolerant species, interactions between temperature and moisture, and developing a cover crop selection tool are ongoing priorities.
This field day took place on the traditional and unceded territory of the Sylix people.
