Twenty years ago, Arbon wheat grower Hans Hayden wrote his agronomy master’s thesis on direct seeding winter wheat into summer-fallow fields. He found that if he placed his fertilizer beneath his wheat seed rather than directly next to it, he could double his yields.

Left: Postdoctoral fellow Carl Bradley evaluates root infection in wheat seedlings caused by fungi that were isolated from infected plants in Idaho fields last summer.

Since that time, Hayden has kept on direct seeding—drilling his new wheat seed into the stubble of last season’s crop. “It saves tillage, it saves moisture, it saves erosion, it saves money, but there are stumbling blocks,” he says. Growers need a better understanding of the complexities of soil moisture retention, root diseases, and soil biology, but research examining direct seeding has been slow in coming.

“Farmers are way ahead of the research,” says Hayden, chairman of the Idaho Wheat Commission. “There’s a book’s worth of agronomy to be written.”

This spring, scientists with the UI’s College of Agricultural and Life Sciences will add chapters to that book. In a multi-year, tri-state project led by David Weller of the USDA Agricultural Research Service at Pullman, WA they’ll follow a recently completed survey of disease organisms in eastern Idaho soils with field studies on Hayden’s farm at Arbon and Gordon Gallup’s farm at Ririe.

Disease control is key to successful adoption of direct seeding, says Bob Forster, UI extension plant pathologist and the project’s Idaho coordinator. That’s because the practice, which is perfect for erosion control, is also nearly perfect for cereal root disease development. “You’re violating a basic rule of disease prevention when you direct seed,” says Forster. “You’re expecting seedlings to run the gauntlet of disease organisms on the soil surface and go on and produce a normal crop.”

On Hayden’s and Gallup’s farms, Forster will conduct side-by-side comparisons of conventionally tilled and direct seeded crops. Starting with spring wheat this year, he’ll eventually evaluate a full rotation of other direct seeded crops. To eliminate the impacts of plant diseases and determine the full yield potential of the sites, he’ll fumigate some strips.

Research partners include Idaho State University soil ecologist Terry McGonigle, who will study the role of beneficial soil mycorrhizae; UI wheat breeders Robert Zemetra and Ed Souza, who will provide breeding lines to be screened for resistance to root diseases; UI plant pathologist Louise-Marie Dandurand, who will explore the potential for controlling cereal root diseases with green manures; and Weller, who is evaluating biocontrol agents that may protect grain seed from disease.

Gallup, vice president of the Idaho Grain Producers Association, has also been direct seeding for two decades. “It’s been working very well and I think it’ll work about anywhere,” he says. “But you have to figure out the system that works for you.”

Gallup’s grain fields aren’t plagued with soil diseases. He’d like the project to answer his questions about improvements in the soil’s organic matter levels and water-holding capacity.

“There are so many interlinked factors, it’s been hard to segregate them out and do research,” says Hayden. “We have a lot more questions than answers.”

But there’s no question that Idaho’s grain growers must find ways to compete more effectively with other countries, many of which are direct seeding far more extensively.

“We’re all looking for ways to cut our input costs—and direct seeding has definitely cut my input costs,” Gallup says.

© 2002 University of Idaho, College of Agricultural and Life Sciences.