In the USA, most corn stover currently remains in fields as crop residue that provides soil erosion control and maintains soil organic carbon levels. This stover is a potential biofuel feedstock for direct combustion, pyrolysis, and ethanol fermentation. At a research site in south central Wisconsin, the northern edge of the US Corn Belt, corn grain harvest averaged 9.8 Mg ha(-1) DM over a 6-year period, 1997 to 2002. Removal of all stover could recover an additional 7.2 Mg ha(-1) y(-1) DM and, in the process, remove an additional 47, 6, 81 and 197 kg ha(-1) y(-1) of N, P, K and calcium carbonate equivalent, respectively. The fertilizer replacement cost for stover removal is 32 $ Mg-1 DM, which is 95% of the fertilizer value of the grain. However, most of the N, P, K and alkalinity of the stover is found in the leaves, stalk, and husks, not in the cob. At our study site, complete stover removal would export 235 $ ha(-1) y(-1) of fertilizer and limestone, mainly as K, while cob export would be worth 20 $ ha(-1) y(-1) in nutrient equivalents. Based on this research, removal of cobs only is equivalent to 16.6% of total stover removal but with a greatly reduced fertilizer replacement cost of 17 $ Mg-1 DM and the same energy density. (C) 2010 Elsevier Ltd. All rights reserved.