This study presents a linear profit model with combined economic and environmental factors for a switchgrass-for-biofuels agricultural system in the southeastern U.S. The objectives are to establish conversion-to-switchgrass thresholds for various market prices and identify policy incentives that would ensure economic profit while also maximizing environmental benefits (carbon sequestration, displacement of fossil fuels) and minimizing negative impacts (global warming potential, nitrate loss). Weighting factors are chosen to represent incentives and penalties by assigning value to the impacts. With no other incentives, switchgrass market prices of at least $51 and $58/dton would be needed in order to make a profitable switch from corn/Conservation Reserve Program (CRP) lands and cotton, respectively. At a mid-range offering of $50/dton, feasible carbon credit prices of $3/ $8/ $23 per metric tonne CO(2)e would incentivize conversion from corn, CRP, or cotton, respectively. Similarly, a water quality penalty of $0.20/ $3/ $2 per kilogram NO3-N leached would incentivize the same conversions with resultant watershed improvement. At a lower price of $30/dton switchgrass, incentives based on valuation of ecosystem services begin to exceed feasible ranges of these valuations. (C) 2012 Elsevier Ltd. All rights reserved.