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Dryland Cropping, Replant Disease, Christmas Trees, Soul of Soil

Posted by | September 23, 2009

WSU Scientists Win $1 Million Grant to Explore Organic Dryland Cropping Systems

Replacing costly chemicals with new crop rotations and no-till technology to raise dryland crops such as wheat and barley organically will be the focus of a team of WSU scientists thanks to a $1 million grant from USDA’s Integrated Organic Program.

“This adds an important new dimension to our organic agriculture program,” said Dan Bernardo, dean of WSU’s College of Agricultural, Human, and Natural Resource Sciences. “While we’ve received a lot of publicity in recent years for being the first in the country to offer a four-year degree in organic ag, we have been conducting research in organic systems for years. This grant allows us to continue leading the way in translating some of the most economically sound practices of organics to dryland cropping systems.”

“We’re trying to make organic dryland wheat production agronomically and economically successful to benefit both the growers and the environment,” said Professor Rich Koenig, co-principal investigator for the grant and chair of WSU’s Department of Crop and Soil Sciences. Koening is part of a multi-disciplinary team of scientists and Extension educators from WSU and other institutions who are collaborating on the project.

The research will explore weed control, soil fertility and the economics of growing wheat organically. Primary tools include the use of seven different rotation crops, including alfalfa, which help fight weeds and fixes nitrogen in the soil. Organic alfalfa is a high-value commodity that would help the bottom line for growers using the dryland cropping system. Dry peas, another rotation crop in the project, serve as a green manure fertilizer.

Koenig said the research team also will examine the effectiveness of using minimally invasive tillage on the project as a way to control weeds and minimize soil erosion.

“We’re trying to make organic dryland wheat production agronomically and economically successful to benefit both the growers and the environment.” — Rich Koenig, co-principal investigator for the grant and chair of the Department of Crop and Soil Sciences

Learn more about crop and soil science research and education at WSU by visiting:

Extension Campaign on Replant Disease Prevention Pays Big Dividends for Tree Fruit Industry

Fumigating an old orchard then replanting it with new rootstock improves young tree growth and dramatically increases fruit yields, and consequently, the bottom line. But it has taken decades of education and advocacy by WSU Extension Educator Tim Smith for the practice to become the rule rather than the exception.

“Industry leaders credit Tim with helping growers understand the necessity, benefits and techniques of how to fumigate new orchard plantings,” said Ray Faini, director of WSU Chelan County Extension. “The rapid and vast replanting that has occurred over the past 20 years, bringing new varieties to market, could not have happened without this work.”

Smith started his program in the 1980s, by setting up several fumigation and post-plant treatment demonstrations trials. “These demonstrations take five to seven years to complete, so no one in the U.S. had ever documented the benefit of fumigation beyond improved growth in young trees,” he said. Smith was the first to demonstrate a significant increase in yield among properly treated trees.

Over the years, he has shared that information at grower meetings, lectures, in grower magazine articles, at plot tours, on Web sites and at international and national meeting presentations. As a result, an ever-increasing percentage of replanted orchards have been fumigated. Smith said that of the approximately 110,000 acres of Washington state orchards replanted over the past 20 years, 42,500 have been fumigated.

Planting new root stock on land long used to produce tree fruit has always had negative consequences. In some cases, replant disease can cause up to 100 percent crop failure, but losses average about 20 percent.

“Orchard replant disease has most likely been the most serious disease in Washington state tree fruits over the past several decades,” Smith said. “Total loss of apple production value due to the effects of this disease over the last 20 years exceeds $1.45 billion.”

Smith also noted that the best way to control almost any plant disease is to build in resistance through breeding. “Some of the biggest breakthroughs are in new rootstocks — some are much more tolerant to the soil conditions that lead to replant disease,” he said.

Overall, he said, the increased use of fumigation protocol and new varieties of root stock “really hold out a great deal of hope that someday we may be able to fumigate, plant new root stock and have respectable growth on an old piece of land.”

First season difference in a replanted orchard.

For more information on orchard planting, please visit:

Growing Better Christmas Trees

After a week of visiting various locations in Oregon and Washington, the ninth International Christmas Tree Research and Extension Conference capped off its annual meeting last week with a tour of the 18 acres of Christmas tree research plots at the WSU Puyallup Research and Extension Center.

“This is a group that involves the leading Christmas tree researchers from around the world,” said WSU plant pathologist and internationally known Christmas tree researcher Gary Chastagner, who hosted the tour. “Getting together allows us to learn about what each other is doing and to develop cooperative projects where we can work on common issues that are affecting the Christmas tree industry.”

Christmas trees are a significant industry in the Pacific Northwest.

“Washington and Oregon provide more than 10 million Christmas trees annually, or about 35 to 40 percent of the trees grown in the United States,” Chastagner said. “We are the country’s largest production region, and it’s a multi-million dollar industry.”

The tour focused on two major issues: Identifying and evaluating species and genetic stock for high moisture and needle retention characteristics and evaluating the susceptibility of true firs to Phytophthora root rot.

Chastagner demonstrated the approaches he and his team have developed for evaluating needle retention. With more than 90 percent of Northwest-grown Christmas trees being exported out of the region, it’s critical that trees retain moisture and needles through the shipping process and, ultimately, in the homes of consumers.

Danish researcher Ulrik Neilsen with the University of Copenhagen said that’s a crucial issue for his program, and one of the reasons he was eager to see Chastagner’s current research.

“Moisture content — being sure that the needles stick to the trees — that’s a very serious issue,” said Neilsen. “We started working with Washington State University and Gary Chastagner about ten years ago, looking into post-harvest quality of trees. That’s one of the things that you are very good at in Washington, being one of the pioneers in the area of evaluating trees.”

The group toured four trial plots where Chastagner’s team is evaluating Phytophthora root rot susceptibility in 14 true fir varieties. The disease is a common problem in the production of the popular Noble fir, particularly in areas with high soil moisture like the maritime Pacific Northwest.

The benefit of the group’s annual gatherings, and especially of the farm tours, goes beyond scientific collaboration and comparing research results, said Chastagner.

“We learn things every place we go, from the growers all the way up to our fellow scientists,” said Chastagner. “Sometimes it’s the grower who is doing a certain thing, but he may not understand why it’s working. When you’ve been in the business of research you understand some of the issues, and you’re constantly looking for clues to how to solve problems.”

Gary Chastagner

WSU Christmas tree expert Gary Chastagner (top right) addresses an international group of researchers at a recent tour of WSU Puyallup’s research plots. Bottom: an example of a tree with Phytophthora root rot alongside healthy ones.

Learn more about what WSU is doing to improve the quality and profitability of Christmas tree production by visiting

The Soul of Soil

They call her Dr. Dirt. It should be Dr. Soil. The distinction is important, says Joan Davenport, a professor and soils scientist at WSU.

“You must know the difference between soils and dirt before you earn the right to malign soils by calling them dirt.”

Certainly no one wishes to denigrate soils. To help people avoid that gaffe, Davenport explains the difference. Dirt is dead, she says, while soil is full of microscopic life. Soil provides our food, supports our forest and enriches our lives. Dirt gets under your nails and into the carpet. Soil is “the upper skin of the Earth.”

Yet, despite all of soil’s benefits, it’s often treated like dirt: “We walk all over it!” Davenport says.

Davenport brings her love of soil to a new online course this fall. Soils 201 is designed for those seeking a degree in agriculture or earning WSU’s organic agriculture certificate.

The three-credit course includes a lot of multimedia, such as animations and videos, but a shovel is also handy. In one assignment, students dig up soil and put it in a plastic bag with a piece of white paper. A week later, they report on what happened to the paper and if they found any worms or insects.

When the assignment ends, Davenport tells students to “feel free to put the soil back into the ground where you dug it.” She often takes a protective approach to soil.

“I get very upset when I see land left to erode,” she says, “or people dumping waste on the soil that the soil cannot deal with.”

Davenport lives in Prosser. She’s an avid vegetable gardener, and she and her husband also grow wine grapes. She nourishes their patch of soil by composting kitchen wastes “to give them back to the land.”

She taught a graduate level online soils class last fall and has taught the soils module of WSU’s viticulture certificate program online since 2006.

“The viticulture program convinced me that online teaching could be as effective as live teaching,” she said. “In all my online teaching experiences, I have really appreciated the diversity of students and how we interact.”

Davenport’s interest in soils began in high school, when she worked on an organic farm. She earned a bachelor’s degree in plant science from Rutgers in 1978, a master’s in soil management from Iowa State University in 1981, and a doctorate in soil chemistry from the University of Guelph in 1985.

“I am always interested in getting down and dirty about soils,” Davenport says.

— Richard H. Miller, Center for Distance & Professional Education

Joan Davenport

Joan Davenport gets down and dirty about soil.

To learn more about online organic agriculture education at WSU, please visit:

To learn more about WSU’s professional certificate programs in viticulture and enology, please visit: