596 Agronomy Journal • Volume 106, Issue 2 • 2014 Biofuels Maximizing Land Use during Switchgrass Establishment in the North Central United States Janet L. Hedtcke, Gregg R. Sanford,* Katherine E. Hadley, and Kurt D. Thelen Published in Agron. J. 106:596–604 (2014) doi:10.2134/agronj2013.0410 Copyright © 2014 by the American Society of Agronomy, 5585 Guilford Road, Madison, WI 53711. All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. ABstRAct Switchgrass (Panicum virgatum L.) grown under three differing establishment methods was evaluated for yield, quality, and potential ethanol production across seven environments in Wisconsin and Michigan. e three establishment methods included: (i) June seeding into fallow ground; (ii) June seeding following winter rye (Secale cereale L.) forage; and (iii) August seeding fol- lowing winter wheat ( Triticum aestivum L.). Planting switchgrass in June was successful following the rye forage crop, but plant- ing in August aſter wheat resulted in complete stand loss. While harvested biomass in a two-cut system was equal to or greater than that realized in a one-cut system (6.9 vs. 6.8 Mg ha –1 ), biomass quality for ethanol production was highest following a killing frost (226 vs. 224 g ethanol kg –1 biomass). e higher overall biomass production in the two-cut system generally compensated for this difference however, with ethanol yields similar between the two systems (1950 vs. 1970 L ethanol ha –1 for the two- and one-cut system, respectively). In addition to ethanol production, we found that forage nutritive value in the first cut of the two- cut system was of sufficient quality to satisfy the dietary needs of several classes of livestock. Harvesting established switchgrass for hay with an early season cutting in a two-cut system provides producers with an alternative forage source while not affecting total seasonal biomass yield if harvested at the appropriate growth stage and cutting height to leave sufficient photosynthetic material for regrowth. J.L. Hedtcke, West Madison Agricultural Research Station, Univ. of Wisconsin–Madison, 8502 Mineral Point Rd., Verona, WI 53593; G.R. Sanford, Dep. of Agronomy, Univ. of Wisconsin–Madison, 1575 Linden Drive, Madison, WI 53076; K.E. Hadley and K.D. helen, Dep. of Crop and Soil Science, Michigan State Univ., 512 Plant and Soil Sciences, East Lansing, MI 48824. Received 27 Aug. 2013. *Corresponding author (gsanford@wisc.edu). Abbreviations: a.e., acid equivalent; a.i., active ingredient; ARL, Arlington; CP, crude protein; KBS, Kellogg Biological Station; NDF, neutral detergent iber; OM, organic matter; RIO, Rio; SC, Sugar Creek; STK, soil test potassium; STP, soil test phosphorus; TDR, time domain relectometer; VMC, volumetric moisture content. Ethanol and other biofuels have the potential to replace 30% or more of the gasoline demand in the United States by 2030 (U.S. Department of Energy, 2011). Presently, the majority of domestic ethanol comes from corn (Zea mays L.) grain, but the long-term sustainability of grain ethanol is questionable as it may increase competition between food, feed, and fuel interests (USDA-ERS, 2013). Switchgrass has been identi ied as a candidate bioenergy crop in recent decades by the U.S. Department of Energy, particularly as a second-gen- eration feedstock for conversion to liquid fuels (Monti, 2012). Recent advances in cellulosic conversion technology and the development of large-scale cellulosic ethanol production facili- ties have made switchgrass a viable alternative to corn grain ethanol (McLaughlin et al., 2002). Switchgrass is attractive as a biofuel crop because of its adaptability from Canada to Texas, its ability to grow on marginal, highly erodible, and drought- prone soils, and its environmental beneits which include C sequestration and wildlife habitat (McLaughlin and Walsh, 1998). It can also be grown and harvested using existing forage produc- tion equipment, reducing potential barriers to farmer adoption. A signi icant number of producers surveyed in Tennessee and Illinois indicated that as production technology and tech- nical assistance become increasingly available, and as demand creates a viable market for biomass, they would be interested in growing switchgrass on their farms (Sanderson et al., 2012). hey may, however, be hesitant to do so if income losses cannot be ofset during the slow establishment period of switchgrass. Although switchgrass can be harvested in as little as 2 yr from establishment (Vogel et al., 2002), it may not reach its full yield potential until the third growing season in the colder climates of the north central United States. Economically feasible systems must therefore be designed which can carry a producer through the critical establishment period. he purpose of this study was threefold and sought to: (i) evaluate two cropping options with small grains (winter rye and winter wheat) from which farmers could realize economic gains during the estab- lishment phase of switchgrass while not reducing subsequent switchgrass productivity; (ii) to evaluate the potential tradeofs of switchgrass managed as a dedicated bioenergy crop (October harvest) vs. a dual-use feed and biomass crop (two cuts; June and October); and (iii) to determine the quality of biomass and theoretical ethanol yield produced under the one-cut and two- cut harvest management strategies. Our initial three hypoth- eses were that: (H 1 ) A rye forage crop preceding switchgrass Published March 6, 2014