Probably 40% of our land (sand) should never have a stover harvest.  It's the other 60% that I am sure I can sustainably  harvest 1-2 tons of biomass from and we have the data to show this.   Course soils just burn through OM to quick for it ever to be practical except for cobs maybe.   Cover crops is changing the equation significantly.  

I think it will end up being "prescription" base residue harvesting.    Hillco's machine I believe is aiming for site specific residue harvesting. 

http://agriculturalmachineryengineering.weebly.com/uploads/9/0/5/7/9057090/asabepaper121337628.pdf