Tips for downy brome control
Downy brome (Bromus tectorum L.) is found throughout Nebraska and is one of the most serious weeds in western Nebraska. Lack of control can be costly to both crop and livestock producers. It is especially troublesome in alfalfa, winter wheat-fallow rotations, continuous winter wheat, rangeland, waste areas, roadsides, shelterbelts, fence rows, and railroad rights-of-way. It invades overgrazed pastures and rangelands and is spread when the long awns on seeds attach to cattle. Seeds also are spread by hay, combines, grain trucks, and in contaminated winter wheat seed.
Downy brome is known by a variety of names including cheatgrass, cheatgrass brome, downy bromegrass, military grass, wild oats, downy chess, and cheat. Downy brome may be called cheat, but cheat (Bromus secalinus L.) is actually a different weed. Cheat always heads out above the wheat. Two other annual bromes often are confused with downy brome: Japanese brome (Bromus japonicus Thunb. ex. Murr), which is more common in western Nebraska, and hairy chess (Bromus commutatus Schrad), which is more common in eastern Nebraska. Both are more prevalent in pastures and waste areas but can be found in winter wheat. This discussion of downy brome also pertains to Japanese brome and hairy chess.
Downy brome is a winter annual and thrives in all soils. This weed has an extensive shallow root system and roots with many hairs that enable the plant to extract much of the soil water. A downy brome density of 50 plants per square foot can remove soil water to the permanent wilting point to a depth of about 2.5 feet. Downy brome is thus very competitive with winter wheat for soil water and nutrients. When under stress, plants only 1 to 2 inches tall can produce seed. Plants under stress from tillage or harsh environments divert more of their photosynthetic energy to seed production than undisturbed plants or plants growing in more productive environments.
At Alliance and North Platte, moderate (one to two plants per square foot) to heavy infestations of downy brome have reduced wheat yields 30-80 percent. Downy brome also can dramatically reduce first harvest alfalfa yields by competing for early season moisture. It also can severely reduce forage quality. Overgrazed rangelands are more easily invaded by downy brome, which reduces economic returns of the grassland.
Downy brome is a palatable grass before the seed heads emerge but becomes unpalatable with maturity. Mature downy brome can injure livestock by causing infection in the eyes or mouth. Mature plants also are a serious fire hazard.