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Title: Grazinglands Research Laboratory (GRL)

item Northup, Brian

Submitted to: Agricultural Research Service Publication
Publication Type: Government Publication
Publication Acceptance Date: 11/5/2007
Publication Date: 2/18/2011
Citation: Northup, B.K. 2011. Grazinglands Research Laboratory (GRL). EcoTrends. Available:

Interpretive Summary: This report presents a summary of the mission and resources of the USDA-ARS Grazinglands Research Laboratory (GRL), and composition of native grasslands on the GRL, for the USDA-ARS “ECOtrends” booklet. The 6,700-acre GRL, located near Oklahoma City, was established in 1948 on a former U.S. Cavalry remount station. The land is planted in numerous forages including native prairie (3,000 acres), cropland planted to wheat (900 acres), improved grass varieties (2,000 acres), and many small research plots of different grasses and legumes. The GRL supports a 250 head cow-calf herd, flocks of hair and wool type sheep, and several hundred stocker cattle each year. The mission of the GRL is to develop technologies, strategies, and tools to help evaluate and manage economic and environmental risks, opportunities, and tradeoffs, for integrated crop, forage and livestock systems. Soil types include sandy loams and clay loams along streams, and silty-clay loams on the uplands. Annual precipitation (1940-2000) averages 30.9 inches, but has varied from 6.5 to 45 inches. Droughts are common and can last for several years. The native vegetation is southern tallgrass prairie, which can reach 3 to 9 feet in height. Depending on growing conditions, 60 to 90% of annual forage production is generated by the grasses big bluestem, indiangrass, switchgrass, and little bluestem. A large number of other perennial warm-season and cool-season grasses and broadleaf forbs are also present. Species composition and productivity of the native prairie can change in response to management and precipitation. As the dominant grasses decline in importance, they are replaced by less-common species. This change is not permanent and the dominant tallgrasses will normally return with increased precipitation and/or reduced grazing pressure.

Technical Abstract: Summary only.