Scott: Actually, it's a bit more complicated than that.
First, for the record, as currently produced, ethanol takes somewhat more BTUs to produce that it has in it, mostly due to distillation costs for water removal. I suppose there are ways around that, but the only reason ADM makes ethanol is that the US government pays them stacks of cash to do so. Standard US government corruption at work, ad nauseum.
The flip side of the use of readily available fertilizers, pesticides, and herbicides is bin busting crop surpluses, with con-commitant price depression, along with the fact that there are just two buyers of agricultural grain products in the US -- ADM and Cargill -- both of whom have been convicted, more than once, of price fixing.....
Another problem we will be facing soon is that the crops we produce use tremendous amounts of petroleum to grow -- all the pesticides are petroleum based, and the chemical and physical energy required to make them from raw materials comes from either coal, diesel fuel, or natural gas. Ammonia fertilizers are also derived directly from natural gas, and require considerable chemical and physical energy to make.
Sooner or later we are going to be in a bind here (not that I've not seen it for the last 30 years or so, but then I've been in the environmental analysis and/or plant physiology graduate programs that long), because petroleum isn't going to last forever.
Biofuels help, but they will not replace petroleum base fuels unless we have a radically different agricultural system. With the current way we grow crops in the US, we expend more BTUs than the crop contains......
Peter
