Bioenergy crops compete for cropland with food, fiber, and feed crops. Growing bioenergy crops on non-crop, marginal land offers an avenue to escape the ethical and practical limitations of using cropland. Several studies have used land cover databases to inventory areas of non-crop marginal land; however, the key question is how much of this land its owners would willingly make available. This study explores the existence of marginal land in Michigan and the terms under which its owners would be willing to make it available for growing bioenergy crops. As no market for bioenergy crops currently exists, we used a contingent valuation survey to examine the willingness of landowners to supply land for bioenergy crop production. The supply response questions asked respondents whether they would be willing to rent their existing land for a specific bioenergy crop at a stated price and, if yes, on how many acres. These questions were asked for three types of land: cropland, hay and pasture land, and farmable non-crop land. The four bioenergy crops used were corn stover, switchgrass, hybrid poplar, and native prairie. Land rental rates, which extended below and well above recent rural market rates in Michigan ranged from $50 to $300 per acre. Owners of non-crop marginal land were identified using area-frame sampling, based upon the 2010 USDA Cropland Data Layer (CDL) of land cover. Willingness to supply land was estimated econometrically as a survey-weighted hurdle model comprised of a participation decision probit and an acreage commitment truncated regression.The results reveal three main findings. First, landowners who possess non-crop, marginal land frequently owned cropland. In fact, on average, they owned more cropland than non-crop land. Given the opportunity to rent out either land type for bioenergy crops, they preferred to rent out more cropland. Second, landowners were largely indifferent about supplying land among the three grassy bioenergy crops: switchgrass, mixed prairie and corn stover, but they preferred all of these to hybrid poplar trees. Finally, at the rental rates offered, only one third of landowners were willing to rent out their marginal land to grow bioenergy crops. Consequently, of the three million acres of marginal land that exist in the region, just over one million acres were offered for the grassy bioenergy crops at the highest rental rate offered. That rental rate of $300/acre far exceeds rates currently offered for conventional field crops and corresponds to biomass prices that substantially surpass most estimates of energy companies' willingness to pay. Two major conclusions emerge. First, the preference of landowners to rent out cropland, rather than non-crop land, for growing bioenergy crops highlights how markets for land at the extensive margin inherently link the supply of bioenergy crops to that of food crops. At an attractive rental rate, most landowners prefer to switch crops on cropland, rather than to convert non-crop land to crop use. Second, the reluctance of landowners to convert more than one third of their marginal land for bioenergy crops, even at exceptionally high rental rates, suggests that the supply of marginal land for bioenergy crops is more limited than previously believed, at least based on evidence from Michigan.
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