Ok, I can see how factoring in (or not) land use changes could make a big difference in the numbers. I would however, attribute the cause of that to the poor policy put in place by the governmental bodies not an inherit factor of biofuel production. The subsidies put in place to encourage corn production in particular are unfair and could be the factor leading to those land use changes. I can see how policies boosting the price and lowering the risk of planting corn would lead to land being moved from somewhat natural prarieland or forest to cropland. I might take a more in depth look at both the studies later to compare them.