Long-term agroecosystem research on northern Great Plains mixed-grass prairie near Mandan, North Dakota

Abstract

Sanderson, M. A., Liebig, M. A., Hendrickson, J. R., Kronberg, S. L., Toledo, D., Derner, J. D. and Reeves, J. L. 2015. Long-term agroecosystem research on northern Great Plains mixed-grass prairie near Mandan, North Dakota. Can. J. Plant Sci. 95: 1101–1116. 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 (100.9132N, 46.7710W). 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 2-yr-old or yearling beef steers at four rates [initially 0.98, 1.39, 1.83, and 2.4 animal unit months ha−1]. The experiment generated some of the first information on the resilience of mixed-grass prairie to grazing and drought 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.

Kentucky Bluegrass Invasion Alters Soil Carbon and Vegetation Structure on Northern Mixed-Grass Prairie of the United States

“…The climate is semiarid, continental with long-term mean annual temperature of 4 C and average precipitation of 416 mm year −1 . The two long-term pastures used in the study were established in 1915 on native rangeland that had not been tilled or farmed previously (Sanderson et al 2015). The pastures are adjacent to each other (46°46′11.43″N, 100°54′55.16″W and 46°45′51.03″ N, 100°55′14.46″W) and uniform in slope (<3%) and have soils with a blend of Temvik and Wilton silt loams (Fine-silty, mixed, superactive, frigid Typic and Pachic Haplustolls; USDA-NRCS 2016).…”

“…During the past century, both pastures have been maintained without tillage, fertilizer, herbicide, or fire. Sanderson et al (2015) describe the management details and scientific history of these pastures since 1915. Soils collected and archived from both pastures in 1959 (NGPRL, unpublished annual report) and 1991 (Frank et al 1995) were used for C and N analyses.…”

“…Kentucky bluegrass invasion has also been associated with overgrazing (DeKeyser et al 2010). Recent data from a longterm (100-yr) grazing site at the Northern Great Plains Research Laboratory (NGPRL) near Mandan, ND, have shown aggressive invasion of native prairie by Kentucky bluegrass regardless of grazing intensity (Sanderson et al 2015). The original vegetation at the long-term site was primarily blue grama [Bouteloua gracilis (Willd.…”

“…) Barkworth; C 3 grass] (Sarvis 1920). Increased abundance of Kentucky bluegrass was noted at the long-term grazing site in the 1990s (Frank et al 1995), and its abundance has increased steadily (Sanderson et al 2015).…”

“…Soils from sampling campaigns conducted in 1959 and 1991 at the long-term grazing site have been archived at Mandan. The long-term pastures at Mandan were dominated by blue grama for about 70 to 80 yr (Sanderson et al 2015). We hypothesized that Kentucky bluegrass invasion altered the 13 C and 15 N levels in the soil.…”