This study examines the impact of stochastic harvest field time on profit maximizing potential of corn cob/stover collection in North Dakota. Three harvest options are analyzed using mathematical programming models. Our findings show that under the first corn grain only harvest option, farmers are able to complete harvesting corn grain and achieve maximum net income in a fairly short amount of time with existing combine technology. However, under the second simultaneous corn grain and cob (one-pass) harvest option, farmers generate lower net income compared to the net income of the first option. This is due to the slowdown in combine harvest capacity as a consequence of harvesting corn cobs. Under the third option of separate corn grain and stover (two-pass) harvest option, time allocation is the main challenge and our evidence shows that with limited harvest field time available, farmers find it optimal to allocate most of their time harvesting grain and then proceed to harvest and bale stover if time permits at the end of harvest season. The overall findings suggest is that it would be more economically efficient to allow a firm that is specialized in collecting biomass feedstock to participate in cob/stover harvest business. 1. Introduction The US ethanol demand has steadily increased following passage of Renewable Fuel Standard (RFS) and the Energy Independence and Security Act of 2007 (EISA). Most domestic ethanol production utilizes corn grain as feedstock. Rising corn prices are encouraging current and potential ethanol producers to seek alternative feedstocks, especially cellulosic sources. EISA defines three classes of biofuels, conventional, advanced, and cellulosic. These classes are differentiated based on potential reduction of greenhouse gas (GHG) emissions of 20%, 50%, and 60%, respectively. Cellulosic biofuels are shown to have higher GHG offset rates than grain-based biofuels . Comparatively more GHG can be reduced through the use of cellulosic feedstock such as corn stover comprised of stalk, leaves, husks, and cobs than corn grain to produce biofuels. Because of its potential in reducing GHG emissions, corn-stover-based ethanol can be qualified as cellulosic biofuel per the federally mandated RFS. By 2022, cellulosic ethanol consumption of 16 billion gallons per year will be required, creating a niche market opportunity. Existing biofuel producers are striving to develop cellulosic biofuels that qualify under EISA. Greater reliance on corn stover as a bioenergy feedstock poses a logistical challenge for farmers who face limited
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