Researchers at the US Department of Energy have conducted a detailed study of the albedo (reflectivity) effects of converting land to grow biofuel crops. Based on changes in albedo alone, their findings reveal that greenhouse gas emissions in land use change scenarios represent a net warming effect for ethanol made from miscanthus grass and switchgrass, but a net cooling effect for ethanol made from corn.
Click here to access study. http://pubs.rsc.org/en/content/articlelanding/2016/ee/c6ee01728b#!divAbstract