Washington State University Tree Fruit Research and Extension Center researchers test soil in plot south of Rock Island

ROCK ISLAND — Researchers from the Washington State University Tree Fruit Research and Extension Center recently planted honeycrisp apple trees at the extension’s Sunrise Research Farm for the launch of their soil health study.

WSU is in partnership with the Washington Soil Health Initiative to launch the Long-Term Agroecological Research and Extension site (LTARE) to investigate soil health in fruit trees.

“The goal of the soil health, tree fruit, long-term experiment project is to develop and evaluate management systems that optimize fruit tree health, as well as sustainable soil health management,” said Tianna Dupont, lead researcher for the research and extension center.

The researchers are conducting three trials each year for the next three years on a total of 7.5 acres. Dupont and her team launched the first trial on Tuesday with 2.5 acres at the Rock Island orchard.

There are five different soil treatments the researchers are studying and each of them is replicated six times to make more comparisons between them, Dupont said.

Examples of the soil treatments Dupont provided were a wood chip mulch, focused on water management, and high carbon, focused on building organic matter with compost and manure.

Dupont said fruit growers are interested in soil health studies for various reasons.

“One is to reduce variability,” she said, “because we have variable soils with different size trees. So if we can get everything nice and even it is better for management.”

“Another is to reduce fruit disorders,” Dupont said. “Think of it like spots on your fruit. We don’t want as much of that. So they (growers) can sell more of it; you like it better because it looks prettier.”

She also said establishing practices that can conserve water to buffer environmental stress was a factor.

“With the climate getting warmer, we want to be able to deal with that heat better,” she said. “So if we can have soils that have more organic matter, they buffer that environmental stress better.”

Lastly, she said the study will teach the researchers how to moderate soil-borne disease.

In 2021, the Washington State Legislature funded the Washington Soil Health Initiative with a nearly $2 million annual allocation from the Washington State Legislature.

“We need to invest in our soils so that we can keep having productive orchards and economies,” Dupont said. “So this is just getting started and we are excited.”