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Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)


Natural Resource Management

First Advisor

W. Carter Johnson


The development of a cellulosic ethanol industry is likely to involve the widespread planting of switchgrass (Panicum virgatum L.) monocultures throughout the U.S. Switchgrass fields will likely displace pastureland, woodland, or Conservation Reserve Program (CRP) land rather than productive cropland. The cultivation of marginal or natural lands for switchgrass feedstock may diminish plant and wildlife habitat, which is rapidly disappearing throughout the Northern Great Plains. Moreover, switchgrass may not grow equally well on environmentally diverse land. A diversified feedstock planting would emulate natural plant community distributions with the intention of increasing plant diversity, while retaining field productivity. Diverse polycultures with more numerous functional groups (warm season, cool season, forbs) and greater structural diversity would provide numerous ecosystem services such as wildlife habitat, surface water improvement, and carbon sequestration. This study evaluated the performance of polycultures of native plants from 3 functional groups grown with switchgrass at 3 slope positions (shoulder, midslope, and footslope). Biomass was sampled throughout the year and end-of-season yields were measured. Switch- grass was not equally productive at all slope positions. Additionally, polycultures outyielded the switchgrass monoculture at the shoulder and midslope. The highest diversity polyculture was the most productive at the shoulder slope. This study demonstrated that the most productive field-scale planting was a heterogeneous assemblage of 10 species from 3 functional groups. The results of this study apply to perennial, biofuel fields in the northern Great Plains.

Library of Congress Subject Headings

Switchgrass Energy crops Feedstock Ecosystem management Biomass energy Plant diversity


Includes bibliographical references (pages 67-74)



Number of Pages



South Dakota State University


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