Biomass is what ethanol really needs in order to be a workable answer.....and everyone seems to be intent on running the idea down for one reason or another. Makes no sense to me. 

Sure, you remove more when you harvest the whole plant.  The point of farming is to use the land to produce things which have value and can be sold, producing more from the land is generally speaking considered one of my goals.  I would have assumed other farmers worked with similar aims.     If you aim is to avoid removing any nutrients from the land, you need to go back to grass and graze it.