MANHATTAN, Kan. – Ask any weed scientist what is one of the most pressing challenges they face, and chances are the answer is herbicide-resistant weeds.
For farmers in central and western Kansas, controlling these weeds in a limited-rainfall environment presents a unique management challenge.
The Kansas State University Weed Science group, in conjunction with the Weed Science Society of America and several co-sponsoring commodity organizations, recently hosted a tour of western Kansas for U.S. Environmental Protection Agency officials from Washington, D.C., and the Kansas City regional office.
The EPA enacts usage rules and sets directions on herbicide labels. A tour such as this creates the opportunity for dialog between growers and regulators regarding herbicide use and regulation. Dallas Peterson, K-State Research and Extension weed specialist, said the tour aimed “to help tour participants better understand dryland agriculture and the difficulties of managing herbicide-resistant weeds.”
Tour organizer Phil Stahlman, recently retired K-State weed scientist and professor emeritus, said tour attendance was as high as 30 for some of the locations. “Several meetings with growers, agronomists, and consultants in informal settings provided attendees an opportunity to question and learn about the regulatory process and to provide input on existing and future regulations,” Stahlman said.
Since the first reported occurrence in the 1950s, herbicide-resistant weeds have become an increasingly common issue for farmers in the United States and worldwide. The number of herbicide-resistant weeds continues to increase, and perhaps more importantly, so does the number of weeds with resistance to more than one herbicide.
Because weeds compete with crops for resources – water, sunlight and nutrients – effective weed control is crucial to farm production. Herbicide resistance naturally happens over time when an herbicide or combination of similar herbicides is used too heavily rather than being part of an integrated weed management program. As resistant populations increase, crop yields are reduced by weed competition, and the cost of weed management increases. This results in a loss of income by the producer.
Western Kansas receives, on average, less than 20 inches of rain per year. As a result, crop yields are most often limited by available soil water. Low levels of soil moisture can be managed with proper planning and utilizing dryland cropping strategies. No-till crop production helps conserve soil moisture, but is more reliant on herbicides for weed control than conventional tillage. Thus, herbicide-resistant weeds threaten the viability of no-till production systems.
Over three days in mid-August, the group made stops throughout central and western Kansas to tour agricultural facilities and fields growing a variety of crops. At the stops, tour members interacted with growers, agronomists and retailers. One site in Colby is a food manufacturer that processes sunflower seeds into quality products to be sold in grocery stores. Another stop gave participants a first-hand look at a large dryland farming operation that utilizes strategies to conserve soil moisture such as no-till and crop rotations.
Tour participant Dwight Koops, president of Crop Quest, Inc., said “it was good to see individuals from the EPA interact with growers, retailers and consultants in our backyard.”
The sentiment was echoed by Jamie Green, branch chief for EPA Region 7 Office of Pesticide Programs, saying what a “unique and tremendously valuable opportunity the tour provided for them to visit with producers and engage in open, candid discussions on the challenges faced by farmers in western Kansas.”