Downy Brome - Don't Get Cheated
Dryland wheat farmers in Washington have wheat production down to an exact science - because they must. In the desert and semi-desert climate of eastern Washington, farmers have to know how to squeeze every drop of moisture and every ounce of nutrients out of each acre. If they aren’t able to maximize their efficiency, the unforgiving land will not provide them with a crop.
So it’s understandable that any invader who would try to steal a crop’s precious moisture is dispatched as quickly as possible. The most common invader is the lowly downy brome plant, nicknamed “cheatgrass” because farmers know it will cheat them out of their yields.
“It will absolutely decimate your crop,” said Jason Evers, a crop consultant with Nutrien Ag Solutions. “We try to control the downy brome the best we can, to limit the amount of seed that it produces because if you let it go, it will rob all the moisture from the soil. If they rob that moisture, it will decimate your wheat crop.”
Downy brome is a winter annual weed, with densely hairy leaves and sheaths. This plant ranges in height from 2 to 36 inches. Each plant contains multiple stems that are erect in nature, and at maturity they begin to droop and appear greenish purple in color. Downy brome is found throughout the United States except in the extreme southeast - but in the wheat fields of eastern Washington, it is public enemy number one.
“It’s probably one of the most problematic weed species we have in the dryland northwest,” said Dr Ian Burke, professor of weed science, Washington State University. “It typically emerges with or just after the wheat crop.”
Most farmers have limited options when it comes to managing downy brome. Best management practices incorporate cultural and chemical control measures to eliminate seed sources, contain its spread, and kill existing weeds before they can compete with crops for water resources. Crop rotation is one of the most effective control measures; however, this is not a viable option in the areas of Washington with the least precipitation.
“Everything we do to make the crop grow - planting at the right time, using the right seed rate, using the right row spacing - all the things we consider good farming; that’s weed management,” said Burke. “Herbicides can take us over the top and make our fields nearly weed-free.”
Weed-free fields mean that we can make more efficient use of our natural resources, and in the end produce a better harvest of grain to keep feeding the world.