MOSCOW, Idaho—When Donn Thill retires today as Idaho Agricultural Experiment Station director, he will cap a 35-year career as a University of Idaho College of Agricultural and Life Sciences professor andweed scientist.
His participation in agricultural research goes beyond that to working during the summer as a high school student for the U.S. Department of Agriculture Agricultural Research Service.
Thill grew up in Uniontown, the grandson and son of men who served important roles in the community’s agricultural industry.
His role as the UI station’s director connected him, symbolically at least, to roots deeper still, to a first field season that began in early 1892, months before the university’s first classes met.
The changes in agriculture nationwide and the Palouse have been enormous since the station’s founding. Even during his career as a weed scientist, discoveries about the basic science of weed control have expanded dramatically.
Early in his career, wild oats posed a major problem for farmers by cutting wheat and barley yields. Then a new herbicide, Hoelon, emerged and solved the problem.
As weed scientists learned more about their targets, they better understood how herbicides worked. That helped to develop new weed control chemicals that were more precisely targeted. “We went from working with chemicals that required us to apply a pound an acre to new ones that required a half-ounce an acre,” Thill said.
The research was focused on applying the knowledge to problems.
Early in his career, farmers began pioneering new tillage methods that avoided plowing to prepare the ground for planting. Advocates reported that no-till or reduced-tillage farming reduced soil erosion, improved soil quality and could cut farmer’s fuel expenses.
Weeds were a bugaboo, though, that could reduce yields and undermine other benefits of no-till farming.
Thill, his students and colleagues went to work on theissue. Combining the herbicides Hoelon and Glean in fall applications proved effective in controlling downy brome – better known as cheatgrass – and broadleaf weeds for up to a year.
“We did a lot of work with sulfonylurea herbicides. That led me into another branch of research herbicide-resistant weeds. Because the first sulfonylurea-resistant weed was one we found in 1987 south of Lewiston on acooperator’s farm that we had worked on for several years,” Thill said.
“From the time of the herbicide’s first release until the time of the first resistance was very short, five years,” Thill added.
His interest led to a major project that produced one of University of Idaho Extension’s most popular publications among farmers: “Herbicide-Resistant Weeds and Their Management,” PNW No. 437.
First published in 1993 and revised five times since, the bulletin covers weeds across the Northwest and recommends strategies farmers can use to lessen the chance weeds will become resistant to herbicides.
Herbicides kill plants by blocking chemicals they need to survive. Resistance typically develops because an extremely small number ofplants in an area are genetically resistant to the herbicide’s effects. Repeated use of one herbicide in the area “weeds” out plants that are susceptible, allowing the resistant plants to grow in number.
The bulletin authored by Thill and fellow weed scientists Joan Campbell at UI and Carol Mallory-Smith and Andy Hulting of Oregon State University lists 18 groups of herbicides. Each herbicide group attacks different chemical pathways.
Switching herbicide groups stops weeds resistant to one group from multiplying.
In 2007, Thill shifted gears from serving full time as a weed scientist to serving as superintendent of the Palouse Research, Extension and Education Center based on the UI’s Moscow campus. He became IdahoAgricultural Experiment Station director in 2009.
The Moscow center includes two research farms, one just east of town and the other near Genesee, and beef cattle barns and pastures, a dairy and a sheep farm. The center is critical to the work of more than 200 campus researchers.
As experiment station director, Thill oversaw the university’s and the state’s eldest and most extensive research units.
The Idaho Agricultural Experiment Station was established 123 years ago to serve the state’s farmers and ranchers. The Palouse center, like seven others near Parma, Caldwell, Twin Falls, Kimberly, Aberdeen, Tetonia and Salmon, house UI research and extension efforts.
As part of Thill’s retirement celebration earlier in July, College of Agricultural and Life Sciences Dean John Foltz noted that Thill had driven more than 1 million miles during his 35 years as a researcher. Earlier in July, he made a week-long tour of the research and extension centers, logging another 1,400 miles to add to the total.
Thill’s expanded duties led him to work closely with farmers, Idaho State Department of Agriculture officials and commodity commissions, including the Idaho Potato Commission, Idaho Wheat Commission, and Idaho Barley Commission.
In 2011, Thill was party to the talks that led to a unique agreement with Limagrain Cereal Seeds, the U.S. subsidiary of the European seed company giant, to share wheat variety development. The Idaho Wheat Commission endorsed the deal and agreed to fund a molecular geneticist to help the College of Agricultural and Life Sciences take advantage of the latest advances in wheat breeding.
Even with all of the advances in molecular biology, genetics and other agricultural technologies based in laboratories, Thill said that if he were just starting his career, he suspects he’d follow a similar path.
“I think I would still choose to be an agronomist, which is really what a weed scientist is, looking at how to grow crops better, because I’ve always liked boots-on-the-ground kind of work,” he said.