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ARS Home » Plains Area » Mandan, North Dakota » Northern Great Plains Research Laboratory » Research » Publications at this Location » Publication #87224
Title: SEASON-LONG GRAZING OF SEEDED COOL-SEASON PASTURES IN THE NORTHERN GREAT PLAINS.

Author
item Karn, James
item Ries, Ronald
item HOFMANN, L - RETIRED; ARS COLLABORATOR

Submitted to: Journal of Range Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/27/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Introduced cool-season grasses are generally recommended only for spring and fall grazing in the Northern Great Plains. However, if these grasses could be used for season-long grazing they would be an attractive alternative to native mixtures for reseeding disturbed lands. A study was conducted near Mandan, ND to determine the effect of season-long moderate (4.7 acres/steer/140 days) and heavy (3.1 acres/steer/140 days) stocking rates on weight gains of yearling Hereford steers grazing crested wheatgrass (CW), western wheatgrass (WWG), smooth bromegrass (SBG), and flat and rolling native rangelands. Steer weight gains were not different among CW, WWG, SBG, and flat native pastures, but gains were lower on rolling native pastures. Weight gains per steer were 8% higher on moderate pastures, but gains per hectare were 39% higher on heavy pastures. Steers spent more time grazing on SBG than WWG, CWG, or flat native pastures, and they also spent more time grazing on heavy than moderate pastures. Seeded cool-season grasses produced season-long weight gains comparable to flat native, and superior to rolling native pastures, even when grazed at a stocking rate 80% higher than recommended for native rangeland by the NRCS (1984). These results indicate that contrary to popular belief introduced cool-season grasses can be grazed season-long in the northern plains in areas where precipitation and environmental conditions are comparable to central North Dakota. Use of introduced cool-season grasses would make it easier for producers to reseed disturbed lands or to alternate between crops and perennial grass production, because introduced cool-season grasses have less expensive seed, they are easier to establish, and they can be grazed sooner after establishment than native mixtures.

Technical Abstract: In the semi-arid Northern Great Plains, cool-season grasses are generally recommended for grazing only in the spring and fall. A study was conducted near Mandan, ND to determine the effect of moderate (1.6 AUM/ha) and heavy (2.4 AUM/ha) stocking rates on weight gains of yearling Hereford steers grazing crested wheatgrass (Agropyron desertorum) (CWG), western wheatgrass s(Pascopyrum smithii) (WWG), smooth bromegrass (Bromus inermis) (SBG), and flat (class II and III) and rolling (class IV and VI) native rangelands. Studies were conducted over a 140-day grazing season during 3 summers from 1992-1994. Grazing was initiated in mid-May and terminated the first of October. At the end of each grazing season forage samples were clipped inside and outside of randomly located cages in each pasture. Animal activity data were collected for 9 days during August and September 1994. Steer weight gains were not different (P<0.05) among CWG, WWG, SBG and flat tnative pastures, but weight gains were lower (P<0.05) on rolling native pastures. Weight gains per steer were 8% higher (P<0.05) on moderately grazed pastures, but gains per hectare were 39% higher on heavy grazed pastures. Steers spent more (P<0.05) time grazing on SBG than WWG, CWG, or flat native pastures, and they also spent more time (P<0.05) grazing on heavy than moderately grazed pastures. Seeded cool-season grasses produced season-long yearling steer weight gains comparable to flat native, and superior to rolling native pastures, even when grazed at an 80% higher stocking rate than recommended for native rangeland by the NRCS (1984). These results indicate that introduced cool-season grasses can be grazed season-long in the northern plains where precipitation and environmental conditions are comparable to central North Dakota.