Tallgrass Prairie Center

Experimental Design

The goal of this study was to determine the number and kind of native perennial prairie species to use to maximize biomass production for electrical generation. In May 2009, 48 research plots were sowed with one of four seeding treatments of perennial vegetation: 1) switchgrass monoculture, 2) 5 species of warm-season grasses, 3) ‘biomass mix’-16 species of warm/cool-season grasses and forbs, 4) ‘prairie mix’- 32 species of warm/cool-season grasses, sedges, and forbs (Table 1, click to view PDF). In addition, seeding treatments were replicated on one of three distinct soil groups: 1) 284 Flager sandy loam – somewhat excessively drained alluvial soil, 2) 177/178 Saude-Waukee loam – well drained alluvial soils, and 3) 585 Spillville-Coland complex– poorly drained alluvial soil. All research plots were mowed in early July 2009 to promote prairie plant establishment (Figure 1). Plots were sampled for biomass productivity in mid-September 2009 (Figure 2).

Tractor   Data collecting
Figure 1. Mowing biomass research plots in the first growing season to improve native plant establishment. Photograph was taken by David O’Shields in late June 2009 at the Cedar River Natural Resource Area in Black Hawk County, Iowa.   Figure 2. Researchers collecting biomass samples in a monoculture switchgrass (Panicum virgatum) plot in September 2009. Photograph was taken by Dave Williams at the Cedar River Natural Resource Area in Black Hawk County, Iowa.