Submitted to: Canadian Journal of Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/24/2015
Publication Date: 10/28/2015
Publication URL: http://handle.nal.usda.gov/10113/61843
Citation: Sanderson, M.A., Liebig, M.A., Hendrickson, J.R., Kronberg, S.L., Toledo, D.N., Derner, J.D., Reeves, J.L. 2015. Long-term agroecosystem research on northern Great Plains mixed-grass prairie near Mandan, North Dakota. Canadian Journal of Plant Science. 95:1101-1116.
Interpretive Summary: Long-term research is critical to understanding sustainability of agroecosystems. We describe the origin and scientific outcomes from a long-term grazing experiment on native mixed-grass prairie at the Northern Great Plains Research Laboratory (NGPRL) near Mandan, ND, USA. In 1915, a stocking rate experiment was started to answer a very practical question: how many acres of rangeland are necessary to support a steer for the grazing season? Four pastures were laid out to accommodate stocking rates of light, moderate, intermediate, and high to determine the long-term effects of stocking rate and climate on cattle production and vegetation. Pastures were stocked continuously from May until October each year from 1916 to 1945. In 1945, the experiment was reduced and the low and high stocking rates pastures have been managed and grazed in approximately the same manner since then. The experiment generated some of the first long-term information on the grazing response of native grasses, relationships of rangeland productivity to soil moisture, and the resilience of native vegetation to severe drought. The long-term experiment demonstrated the resilience of the native vegetation in response to the severe drought of the 1930s. Now in the 100th year, the pastures currently serve as a unique resource to address contemporary questions regarding grazingland management and the environment as part of the Long-Term Agroecosystem Research Network (LTAR) and the National Ecological Observatory Network (NEON).
Technical Abstract: In 1915, a stocking rate experiment was started on 101 ha of native mixed-grass prairie at the Northern Great Plains Research Laboratory (NGPRL) near Mandan, ND (100.9132 N 46.7710 W). Here, we document the origin, evolution, and scientific outcomes from this long-term experiment. Four pastures of 12.1, 20.2, 28.3, and 40.5 ha were laid out and stocked continuously from May until October with two-year-old or yearling beef steers at four rates (average of 85, 102, 134, and 255 kg liveweight ha-1). Results after 30-years of grazing indicated that a moderate stocking rate of 1 two-year-old steer per 2.8 ha or 1 yearling steer per 2.2 ha sustained livestock gains and vegetation. The experiment generated some of the first information on the grazing and drought resilience of native vegetation and relationships of livestock productivity to soil moisture for predictive purposes. After 1945 the experiment was reduced to the light and heavy stocking rate pastures only, which have been managed and grazed in approximately the same manner to the present day. The pastures were used to assess responses of vegetation to fertilizer in the 1950s and 1960s, develop grazing readiness tools in the 1990s, and assess remote sensing technologies in the 2000s. The long-term pastures currently serve as a unique resource to address contemporary questions dealing with drought, soil quality, carbon dynamics, greenhouse gas emissions, invasive species, and climate change as part of the Long-Term Agroecosystem Research (LTAR) Network and National Ecological Observatory Network (NEON).