The emergence of markets for cellulosic biofuel feedstocks may lead to substantive tradeoffs between economic and environmental goals in agricultural regions, and will raise environmental and energy policy concerns. This paper examines the potential tradeoffs between cellulosic feedstock production and water quality and analyzes policy options to address those tradeoffs for a northern corn-belt watershed. Policy alternatives considered include restrictions on total nitrate-N load in the watershed and production subsidies for switchgrass - an energy crop with potential environmental benefits. Restricting nitrate-N loads increases the cost of cellulosic feedstock supply and in some circumstances makes switchgrass production an economical alternative. Switchgrass production subsidies, if sufficiently high can increase feedstock supply while reducing or eliminating the negative effects of feedstock production on water quality.