Dryland Performance of Sweet Sorghum and Grain Crops for Biofuel in Nebraska

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. S weet sorghum is a sugar crop with biofuel potential and has been found to be competitive with corn for theoretical ethanol yield with less energy invested (Smith et al. Biomass yield from SS has been found to be similar across a wide plant population range (Lueschen et al., 1991; Ferraris and Charles-Edwards, 1986). Sucrose concentration in the juice was 7% less but fermentable sugar yield was 14% more with a plant population of 140,000 compared with 70,000 plant ha −1 (Broadhead and Freeman, 1980), and water soluble carbohydrate yield was greater with 160,000 compared with 80,000 plant ha −1 (Martin and Kelleher, 1984). Response to applied N has varied with location. Nitrogen rate did not aff ect fermentable sugar yield (Smith and Buxton, 1993), total and stalk dry matter yield at harvest (Barbanti et al., 2006), or fermentable carbohydrate and ethanol yield (Lueschen et al., 1991). In Louisiana, biomass yield has been shown to increase by 140% with application of 100 kg ha −1 N, but yield was not increased with an additional 100 kg ha −1 N (Ricaud and Arenneaux, 1990). In the same study, total sugar yield was increased by 150% by applying 100 kg ha −1 N, with an increase of only 4% from an additional 100 kg ha −1 N. Sweet sorghum has been found to require approximately 36% of the fertilizer N needed for similar ethanol yield levels in corn (Geng et al., 1989). Total dissolved solid concentration in stalk juice was shown to decrease with increased N rate (Wienden-feld, 1984). Life cycle GHG emissions are restricted for biofuels under the Energy Independence and Security Act of 2007 (available at ABSTRACT Sweet sorghum [SS; Sorghum bicolor (L.) Moench] is a potential biofuel crop for the Great Plains. Sweet sorghum was compared with corn [Zea mays (L.)] and grain sorghum for potential ethanol yield, energy use effi ciency, and greenhouse gas (GHG) emis