Grounding Long-Term Soil Health Tree Fruit Research in Stakeholder Needs

By Molly McIlquham and Tianna DuPont, Washington State University

By addressing the real-world challenges growers face, this LTARE site aims to provide growers with practical solutions to enhance orchard productivity and sustainability.

In the heart of Washington state lies a thriving tree fruit industry, a vital contributor to both the region’s economy and global food supply. But behind the scenes of this flourishing sector are challenges threatening its sustainability. From soil health issues to fruit quality concerns, growers face obstacles that demand innovative solutions.

Recognizing the importance of addressing these challenges, stakeholders from across the industry joined forces to shape the Tree Fruit Soil Health Long-Term Agroecological Research and Extension (LTARE) site in Wenatchee, WA. Through surveys, focus groups, and workshops, their input guided the development of this innovative research site that will provide a space to ask soil management questions for many years.

This LTARE site is part of a network of research sites funded by the Washington Soil Health Initiative, a state program to sustain and enhance soil health across Washington State’s diverse regions and soils.

What soil management challenges do stakeholders face?

To ensure that the LTARE site was grounded in the needs of the stakeholders, site leader Tianna DuPont leaned upon those stakeholders to share their challenges, concerns, and successes in their orchard management—looking to find common priorities that can be answered through investing in soil management.

Key challenges growers stated included:

• Low fruit quality
• Replant disease/nematodes
• Light droughty soils
• Compaction

Generally, the stakeholders expressed that to continue to make a viable operation, they need to understand how soil health is related to tree health, productivity, and fruit quality, as they ultimately get paid based on fruit production and quality.

The soils in Central Washington don’t make answering these soil management questions any easier. Soils in this region tend to be patchy, with many different soil types in small areas, which can make it hard for producers to manage their soils effectively. Some areas also have caliche layers of hardened calcium carbonate, which can restrict root growth and water movement.

Building soil health is both an opportunity and a challenge for perennial crops. Because perennial plants are semi-permanent, there are few opportunities to incorporate organic matter additions and manage disease, but they are generally lower disturbance, which can preserve soil health.

Overall, the priorities she heard encompassed a range of issues. By targeting these key challenge areas, this LTARE aims to provide growers with practical solutions to enhance orchard productivity and sustainability.

LTARE site leader Tianna DuPont says, “The goal of the Tree Fruit LTARE is to develop and evaluate management systems that optimize fruit yield and quality through sustainable soil health management practices.” The project will focus on reducing variability with organic matter amendments, reducing bitter pit and other disorders related to water/nutrient and plant stress, establishing soil health practices to conserve water and buffer environmental stress, and identifying long-term challenges to soil-borne disease and nematodes.

“It will be a team effort to address these challenges. I am glad to be able to support the group, which includes Lee Kalcsits, WSU Tree Fruit Physiologist; Tracey Somera, USDA microbiologist; Jessica Waite, USDA geneticist; Devin Rippner, USDA soil scientist and Chad Kreuger, WSU Extension.”

The results of Tianna’s investigation into stakeholder needs can be found in the WaSHI Soil Health Roadmap.

What research questions should the researchers ask?

So what research questions should Tianna and team ask, and how should the experiment be designed? Designing a long-term experiment is challenging, especially in tree fruit, because apple and cherry varieties that are popular now may only be popular for a few years. The site was designed to ensure it could adapt to changes in the industry. It also needs to be able to adjust to new gaps in knowledge. There is a great interest in soil biology and managing the soil microbiome, especially regarding nutrient cycling, water uptake, and improving root health.

Drawing upon a combination of on-farm practices and research findings, treatments such as water management strategies and organic matter amendments were selected based on their potential to improve soil health and fruit quality.

The LTARE site team has established four primary treatments for investigating reduced disturbance and increased soil organic matter additions:

1. Standard – typical synthetic nutrients and herbicides applied
2. Integrated Organic – tree row cover crop, pre-plant compost and alley cover and tree pruning mowed under the trees
3. Mulch Additions- typical synthetic nutrients and herbicides, with mulch added every three years
4. High Carbon additions- typical synthetic nutrient and herbicide applications, pre-plant compost, and alley cover and tree pruning mowed under the trees

Each year, Tianna and the team meet with the stakeholder advisory team to ensure that the nitty-gritty details of implementing these treatments match what is being done throughout the industry.

For example, at the last advisory meeting, they discussed winter pruning methods, overhead cooling vs netting, herbicides that work, and cultivation timings.

What information will WaSHI provide?

By integrating conventional standards with innovative approaches, the project aims to equip growers with practical tools tailored to their needs. This site will establish best management practices for managing soil health, helping to reduce variability in orchards with organic matter amendments.

As the project progresses, its impact will extend beyond Washington’s orchards, benefiting growers and communities across the region and beyond. It will improve fruit quality by reducing bitter pit—caused by a calcium deficiency —and other disorders related to plant stress. By empowering growers with the knowledge and resources they need to thrive, the LTARE site represents a collaborative effort to ensure the long-term sustainability of tree fruit production by identifying sustainable approaches to managing soil-borne diseases.

The Tree Fruit Soil Health LTARE site demonstrates the value of grounding research in stakeholder needs. By addressing the real-world challenges growers face, the project aims to cultivate a future where tree fruit production is sustainable and resilient to evolving agricultural landscapes.

Find more detailed information about this LTARE site on the Wenatchee LTARE site webpage.

This article was originally published by the Washington Soil Health Initiative.