UO ecologists secure $2 million to boost soil health of Oregon hazelnut farms

A mix of native wildflowers and volcanic rock dust can offer climate resilience for filbert orchards

EUGENE, Ore. (KTVZ) — Ecologists from the University of Oregon have designed a system to improve soil health and strengthen the long-term vitality of the state’s hazelnut industry — and now they’ve received $2 million to test it on 20 farms.

Oregon produces 99 percent of the nation’s hazelnuts, but the escalation of global extreme heat, which brings dry soil and scalded plants, threatens the agricultural productivity of the region.

A promising solution: carpeting the orchard floor with native wildflowers and basalt dust.

“To be resilient to climate change and to minimize climate change, you need healthy soil,” said Lauren Hallett, an associate professor of environmental studies and biology at the UO’s College of Arts and Sciences.

For the past five years, Hallett and her colleague Marissa Lane-Massee, a research assistant at the UO and fourth-generation hazelnut farmer, have worked together to create cover crop seed mixes that keep agricultural soils cooler during increasingly hotter seasons without interfering with the harvest. Compared to bare soil, a blanket of cover crops can better regulate soil temperature and enhance water retention and soil microbiology.

They’ve tested the approach on hazelnut farms managed by Lane-Massee and her family, with promising results. Now, to show how the system might scale up, the research team has received  $2 million from the U.S. Department of Agriculture. They’ll partner with 20 hazelnut farms across the Willamette Valley to demonstrate the ecological and economic benefits and provide incentives and technical support for adoption.

U.S. Sen. Ron Wyden of Oregon established the USDA program through his work on the Inflation Reduction Act. The effort built on his earlier work on the 2018 Farm Bill to promote soil health and climate resilience.

“Oregon is great at both growing things and adding value to them, but we need to make sure we do both in a sustainable way,” Wyden said. “I am always eager to support programs that tackle challenges farmers face while helping address the climate crisis.”

Despite its whispered potential, cover cropping historically has had a negative stigma among hazelnut farmers, Lane-Massee said. The orchard ground is conventionally left bare because of concerns that adding vegetation would tangle up fallen nuts and mess with harvesting, she said. A clean orchard floor is considered a good orchard floor.

“My grandma always said you got to keep the orchard like a golf course, so that when you go to harvest, the nuts roll right across the ground and into the machine,” Lane-Massee said. “But there's also cultural and aesthetic reasons, like wanting an aesthetically pleasing understory with smooth floors and rows that are neat and tidy."

Unlike tangle-prone grasses or weeds, the research team’s cover crop mix includes native wildflowers, including camas, checkermallow and phacelia, that harmoniously follow the hazelnut lifecycle. The cover crops sprout in late fall, grow to a small ground cover in winter and bloom taller during spring and summer. They improve soil integrity by acting as a shield from the sun, retaining soil moisture and preventing erosion.

By autumn when trees drop their hazelnuts, the wildflowers have already died back, allowing for easy, untangled picking. To validate this, Lane-Massee checks how many hazelnuts remain unpicked in each plot after the harvesting machines plow through as part of their data collection process. The ideal is two nuts or fewer to avoid profit losses, she said.

As perennials, the cover crops grow back once the fall rains begin.

“You never have to reseed. It’s a one-time input,” Lane-Massee said.

The cover crop mix will be used alongside basalt dust amendments, which can potentially help mitigate climate change. When basalt gets weathered down by rain or wind, a chemical reaction occurs that removes carbon dioxide from the atmosphere and converts it into stable minerals. These wash into local streams and rivers and eventually flow into oceans where they stay trapped on the seafloor for thousands of years — a tactic to address carbon pollution.

Spreading the dust can also increase the pH of the soil, serving as a carbon-sequestering alternative to conventional lime. The process has the potential to scale up quickly because basalt powder, a byproduct of mining, isn’t in short supply with Oregon’s Columbia Plateau as a local source, Hallett said.

The Lane-Massee Farm is the first hazelnut orchard to use basalt dust amendments and plans to investigate how it can be scaled up to commercial farming. Measuring how much carbon gets stored and the amount of powder to apply for the best results is hard to ascertain, Hallett added, but basalt dust is a very compelling source of permanent carbon removal.

“This is potentially one of the most promising natural climate solutions but also one with the biggest range of uncertainty,” she said.

Moreover, what works in one orchard may not work for another.

“Every farm you go to has a different story,” Lane-Masse said.

In response, the research team will customize the cover crop seed mix to each partnering orchard based on its canopy conditions, including the soil type and amount of sunlight available, and the farmers’ needs.

“I hope that, with the research we're doing, we can offer more of a tailored scientific perspective and experience to what each individual farmer is doing,” Lane-Massee said. “The blanket science will not work for every situation. It's really important that science learns from the people it's trying to help and that farmers learn from science.”

A barrier, however, is the expenses. Currently, native wildflower seeds and basalt dust amendments are not as cost effective or widely available as conventional methods, Hallett said. But in order to make them economically feasible, you need to demonstrate the practice as powerful, she said.

"It’s a bit of a chicken-and-egg problem,” Hallett said.

The research pair said it will likely take a generation, or more, until the soil health management system becomes standard practice. But they believe the new federal backing could be the tipping point in gaining industry and agricultural support.

“I hope some day, when I drive down I-5, I just see fields of wildflowers and happy growers,” Hallett said.

— By Leila Okahata, University Communications

This research was done in collaboration with Lucas Silva, a professor of environmental studies and biology at the UO, and Nik Wiman, an associate professor of horticulture at Oregon State University. The team received support from the U.S. Department of Agriculture and the National Science Foundation.

About the University of Oregon College of Arts and Sciences 
The University of Oregon College of Arts and Sciences supports the UO’s mission and shapes its identity as a comprehensive research university. With disciplines in humanities and social and natural sciences, the College of Arts and Sciences serves approximately two-thirds of all UO students. The College of Arts and Sciences faculty includes some of the world’s most accomplished researchers, and the more than $75 million in sponsored research activity of the faculty underpins the UO’s status as a Carnegie Research I institution and its membership in the Association of American Universities.