Management of Cheatgrass in Conservation Reserve Programs
Fabian Menalled, Cropland Weed Specialist, MSU-Bozeman
Cheatgrass (Bromus tectorum), also known as downy brome, is an annual or winter annual grassy weed widely distributed throughout North America. This 4 to 30 inches tall plant can be easily recognized by its flat leaf blades densely covered with soft hair and its short ligules. Inflorescences are 2 to 6 inches long, dense, slender and usually dropping. At maturity, inflorescences have characteristics 3/8 to 5/8 inch long purplish awns. Thanks to these awns that attach to clothing or animals, cheatgrass seeds spread easily.
This non-native species was first introduced to the United Sates from Asia in packing material. Initially distributed along rail lines, it spread throughout many Sates including Idaho, Nevada, Utah, Colorado, Kansas, Montana, North Dakota, Oregon, and South Dakota.
Cheatgrass competes with more desirable plant species for moisture because of its winter and early spring growth habit. In many situations, cheatgrass can inflict significant economic costs, reducing crop yields and lowering weight gain of grazing livestock. Also, it is a common crop seed contaminant very difficult to be separated from grass seed. Finally, after maturity cheatgrass becomes a fire hazard because it usually dries four to six weeks earlier than native perennials and has a tendency to burn rapidly.
Roundup (glyphosate), Journey (imazapic plus glyphosate), or Plateau (imazapic) can be used to help managing cheatgrass infestations in Conservation Reserve Programs (CRP) land. Roundup can be applied in established CRP to suppress competitive growth and seed production of cheatgrass and other undesirable annual grasses such as cereal rye and jointed goatgrass. However, applications should be done in early spring to prevent weed seed production. Care should be taken to only apply glyphosate to dormant grass to avoid risk of injury of desirable plant species. If perennial CRP grasses have initiated new growth, you could apply glyphosate at its lower recommended rate, but some growth stunting of CRP perennial grasses may occur.
On CRP land, Journey provides pre- and postemergence control of variety of weeds including cheatgrass, downy brome and medusahead rye. Journey may be used prior to planting desirable species on CRP land at rates up to 32 oz. per acre per year. For best results in cheatgrass control, Journey should be applied in late summer or fall before cheatgrass emerges and prior to planting desirable species as it can not me used after newly seeded desirable species have begun to emerge. Spring applications of Journey can be done to increase consistency in cheatgrass control. However, these spring applications should be limited to areas without a large number of desirable plants.
Plateau is a broad-spectrum herbicide that provides control of cheatgrass and other weed species including leafy spurge, foxtails, common lambsquarters and Johnsongrass in CRP and other noncrop areas. The selective activity of Plateau allows desirable native grasses and forbs to re-establish after treatment. For the most effective control of cheatgrass and other bromes, late summer or fall applications of Plateau herbicide, preemergent to germination, are highly recommended.
The integration of chemical management tools with cultural practices is essential to achieve successful control of cheatgrass in CRP. Cheatgrass seeds usually do not remain viable in the seedbank for more than two or three years in the soil. Thus, preventing seed production in the spring reduces the number of seeds in the soil and provides long-term weed management benefits.
Disclosure. Common chemical and trade names are used in this publication for clarity by the reader. Inclusion of a common chemical or trade name does not imply endorsement of that particular product or brand of herbicide and exclusion does not imply non-approval.
Categories: Integrated Weed Management, Herbicides