http://www.agry.purdue.edu/Ext/corn/new ... nd2007.pdfI'm not saying you're wrong, but for further consideration look at the above document which says that the corn yield in Indiana in 1930 was about 25 bushels per acre. Compare this to the modern fertilizer-enhanced, heavily mechanized, irrigated agriculture system which has developed since we started using all of that fossil fuel to power our equipment, about 150. That's about what it is in Iowa too, as I recall generally.
To be sure, we will probably never go all the way back down to 25 because of the modern hybrids and other improvements made to the crops themselves. Then again, as a midwesterner I am sure you have tried to eat feed corn yourself at some point and found it to make you nice and regular, but not too good for people, so to switch to varieties of corn and other crops for people to eat, rather than raw materials for downstream use for feeding animals and other industrial processes (like feed corn and soybeans) will not be the easiest thing in the world either.
One other gap in this post-fossil-fuel scenario is the shortage of people who have, at any time in their lives, worked their asses off in the sun in some hot dry cornfield. You can say what you want about China, but according to the CIA world factbook, 43% of the nation is still employed in agriculture, and most of that is the hard way, where they issue you a shovel and a hoe and a plot of ground and tell you to have at it. In the US, 0.6% of the population feeds the rest of us. that means that 99.4% of us have no clue whatsoever what it is like to go out in the morning and shovel cow shit all day. How you are going to convince some of your squishier suburbanites to do this in order to survive will be a big problem.
The third problem: There is all of this land, and the population density is low, but whose land is it, and will they just let you move out there? Doubtful. A lot of the old homesteads have long ago been folded into giant corporate farms, with political influence and money, and they will be resistant to letting the rabble go out and farm a plot of it. Not to say it won't happen, but that whole system of land ownership will have to be re-thought out.
I suppose there are other problems. I do not know how far west you are, but out in Nebraska and Kansas there is the problem with the depletion of the aquifers, filled by the glaciers and mainly extracted in the last 30 years due to intense well digging and irrigation.... once that water is gone, you're going to have to wait until the next ice age for the deposits to be replenished....
You still have the sun. For now, that's free, but there are a few other problems that are going to make it really difficult to get to some other normal state than what we are right now.
I just hope it happens gradually enough for the farmers to adapt, and for the system to get to some stable state. The bright side of the whole ethanol disaster was that it showed the willingness of the farmers to do something different if properly incentivized. Maybe it will all work out. I hope so.
https://www.cia.gov/library/publication ... os/ch.html