Who is the "we" that has all this land? The federally owned land is not for us to use,it's to look at.That leaves private land,and with the Supreme Court's decision on imminate domain there really is no private property! You just get to use it and pay taxes on it until the government finds a BETTER use for it. You don't really think Exon is going to let a bunch of farmers into the fuel business? Corn uses a lot of nitrogen and that must be replaced in order to grow corn on the same place again. Runoff from fields carries nitrates into rivers and kills fish. Groups of greenies fight each other over this. If there was an easy solution it would,t be a problem!
