|Karl, M - USFS|
Submitted to: Research Update for Fort Keogh Livestock and Range Research Laboratory
Publication Type: Other
Publication Acceptance Date: September 1, 1997
Publication Date: N/A
Technical Abstract: Developing grazing management tactics to best use alien, annual brome infested ranges in the Northern Great Plains requires understanding factors affecting their annual variation in spring forage production. We investigated effects of managerial interventions on production of annual bromes. Samples were collected from a series of pastures at Fort Keogh from 1984 to 1990. Forage standing crops were estimated annually in all pastures just before the grazing season by hand harvesting all herbage above a 1" stubble height in fifteen plots per pasture. From 1984 through 1990 at Fort Keogh, production of annual grasses ranged from 25 pounds per acre in 1988 to 500 pounds per acre in 1990. Annual brome contributed 60 to 90% of this amount. Crude protein of Japanese brome ranged from 13 to 17% in seedlings to 2 to 3% in mature forage, whereas seedheads may contain 8 to 12% crude protein. These forage characteristics suggest early spring is the optimum period for livestock production on brome infested ranges. Variation in the amount of rainfall and available soil nitrogen are probably the major causes for the erratic behavior in forage quality and production. One of the greatest challenges in managing brome infested ranges is predicting when early spring forage production of annual bromes will be adequate to allow grazing that will not severely affect associated perennial grasses. Quantifying population dynamics of annual brome with changes in soil water, soil nitrogen, and seedling density in the Northern Great Plains is needed to develop user friendly Decision Support Systems to aid in management of brome infested ranges.