Smooth Brome Grass - Control in Conservation Reserve Program (CRP) Fields
by Jordan Martincich, Kansas Representative
Smooth brome is a grass that was introduced into the U.S. from Europe in the late 1800s and was widely established due to its resistance to depression-era droughts. Brome is a cool-season grass, which means that it is actively growing at fairly cool temperatures in the spring. The prominent native grasses of Kansas, like big bluestem and Indian grass, are warm-season grasses and begin to grow much later in the spring and even early summer.
How is smooth brome grass identified?
Look for the W or M shape in the leaf. Smooth brome will be one of the first grasses greening up early in the spring. After putting out a seed head in early summer, brome will become dormant. It will green up again in the fall as the temperature begins to cool down. Cool-season grasses are the last grasses to become dormant in the fall. Optimum temperature for cool-season grass growth is 65-75° F, optimum temperature for warm-season grass growth is 85-95° F.
Why is having brome BAD?
Brome forms a thick matt of grass at ground level making it difficult for young grassland birds to move around in search of food while in early stages of development when mobility is key to survival. Brome grass also out competes other native grasses and broadleaf plants. This aggressive nature turns the grass stand into a monoculture and discourages the establishment of wildlife-friendly plants that will attract bugs and insects and consequently feed for young birds.
If you have a Conservation Reserve Program (CRP) contract that requires a native grass cover and you have an invasion of brome grass, this defeats the wildlife benefits. If left unchecked, this may not meet the approved practice cover and may result in noncompliance. Brome is best controlled early before it takes over the entire field. In many cases if native grasses are present on greater than 20 percent of the area with proper management, the native grass will reestablish and begin to flourish within time without needing to be reseeded.
When to spray for brome grass?
Apply herbicide to control brome grass chemically in the fall after a killing freeze (27º F or colder for three consecutive hours or more) for best results. Native grasses are dormant at this time while cool-season grasses are still actively growing. Applying glyphosate within 10 days after the frost is ideal, because the grass is beginning to pull all the moisture and nutrients in the leaves down into the root system to store energy and water during the dormant period. During the winter, the applied chemical has a direct path to the source of the problem, the root system. This method provides better results and less re-growth the following year. Continually monitor these areas because one treatment will not completely eradicate the brome grass.
This is the time to spray. Warm-season grasses are dormant and cool-season grasses are actively growing. You will not hurt the native grass during this period.
Always follow labeling instructions when using herbicides!
How does brome get started in native grass?
If brome is invading your native grass, it is likely encroaching from a nearby roadside ditch, or waterway, or from a remnant in the soil. Brome grows well in poor soils and is found in odd areas where native grass has trouble getting started. Spray for brome along field edges, waterways, and along the tops of the old terraces. These areas may not have been seeded well enough to get established and are likely spots for brome to creep into your fields.
What else besides spraying can I do to control brome grass?
A controlled burn on your CRP field at the right time will increase your chances of eliminating brome grass as well as prescribed grazing. Timing is everything if using fire to control brome. Brome will be stimulated if it is burned during its dormant period. A dormant burn only followed by cattle grazing of regrowth can dramatically reduce smooth brome grass. CRP rules and regulations must be followed for any grazing activities. Burns and other disturbances must not take place during the nesting season. Dormant season burns combined with grazing help focus grazing pressure. It will be damaged during the growing period once most root resources have been invested into the growth of the plant. The best time to burn is when enough dry fuel is present to carry a fire and after the stand has greened up 4 to 10 inches tall. If the plants green up too much, it will be very difficult to carry the fire. The native grasses and other prairie plants will respond well to treatment since it will weaken the cool-competitors.
Helpful Spraying Tips
In the fall consider applying glyphoshate at a higher rate (at least 64 ounces per acre) because the more leaf contact applied through the foliage of the native grass results in better success. You may also use a surfactant or ammonium sulfate to increase glyphosate activity. Always follow label guidelines when mixing chemicals. The best time of day to spray is from 9 a.m.—6 p.m., never at or near dark. Try to apply herbicides on a mostly sunny day and never when overcast. Look for low wind and dust conditions and less than 80 percent humidity. Clay particles in the air absorb chemicals and reduce efficiency. Also, never spray right before a rain.
Remove leaf matter prior to the treatment to maximize results. Defoliation stimulates growth and increases the effectiveness of herbicide applications and can be achieved by burning, mowing, haying, or grazing prior to the chemical treatment. Be sure all CRP rules and regulations are followed. Review your contract with staff at your local U. S. Department of Agriculture (USDA) Service Center before altering the CRP cover.
For more information about CRP or natural resources conservation, call or stop by your local Natural Resources Conservation Service (NRCS) office or conservation district office. The office is located at your USDA Service Center (listed in the telephone book under United States Government or on the internet at offices.usda.gov). More information is also available on the Kansas Web site at www.ks.nrcs.usda.gov. Follow us on Twitter @NRCS_Kansas. USDA is an equal opportunity provider and employer.
This article is also available in
Last Modified: 07/20/2012