Skip to main content
ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #81502
Title: CLIPPING AND JAPANESE BROME REDUCE WESTERN WHEATGRASS STANDING CROP

Author
item Haferkamp, Marshall
item Heitschmidt, Rodney
item KARL, MICHAEL - USDA-FOREST SERVICE

Submitted to: Journal of Range Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/10/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Japanese brome, an alien annual grass, is an important plant species in the Northern Great Plains. Understanding the relationship between this and other species on the range is critical for management of infested ranges. We studied the effect of removing Japanese brome and clipping western wheatgrass on forage production in a western wheatgrass dominated community. During early spring 1993, a wet year, and 1995, a drier year, western wheatgrass shoots were clipped to ground level in May or June and Japanese brome seedlings were left undisturbed or removed in circular plots. We sampled plots on each clipping date and when Japanese brome matured in mid July. Environmental conditions were most favorable for initiation of western wheatgrass shoots and germination of brome seed in fall 1994 and for herbage production in 1993. Clipping western wheatgrass shoots reduced accumulated forage production 205 to 312 lb/acre and weight per shoot 17 to 58%. Western wheatgrass production was 91 lb/acre greater with removal of Japanese brome, while total production was 254 lb/acre less with brome removal. Herbage production of western wheatgrass increased as a result of an increase in shoot density. Weight per western wheatgrass shoot was similar between thinning treatments. Japanese brome contributes to total herbage production on Northern Great Plains rangelands, but its presence can reduce herbage production of western wheatgrass.

Technical Abstract: Japanese brome (Bromus japonicus Thunb.), an alien annual grass, has invaded many northern mixed-prairie plant communities. We studied the effect of removing Japanese brome and clipping western wheatgrass [Pascopyrum smithii Rydb. (Love)] on aboveground forage production in a western wheatgrass dominated northern mixed-prairie community. During early spring 1993, a wet year, and 1995, a drier year, western wheatgrass tillers were clipped to ground level in May or June and Japanese brome seedlings were left undisturbed or removed in circular, 1-m2 plots at a clay-pan field site. We sampled plots on each clipping date and when Japanese brome matured in mid July. Environmental conditions were most favorable for tiller initiation of western wheatgrass and germination of annual brome seed in fall 1994 and for herbage production in 1993. Clipping western wheatgrass tillers reduced accumulated standing crop 230 to 350 kg ha-1 and weight per tiller 17 to 58%. Standing crop of western wheatgrass was increased 102 kg ha-1 with removal of Japanese brome, while total standing crop was reduced 284 kg ha-1 with brome removal. Increased standing crop of western wheatgrass appeared to result from increased tiller density of 68 tillers m-2 rather than increased tiller weight. Removal of Japanese brome from northern mixed-prairie plant communities may increase production of associated perennial grasses, but managers should also expect a short- term decrease in total standing crop.