Well, not quite, unless perhaps I toss in the bird.
Seriously though, I'm really coming along on this whole thing.
The U'ala Piko sweet potatoes I can attest conservatively produce at .5 lb per square foot per year. I've 1500 square feet of those and plan to double that here in the next couple of months. The potatoes alone will give me 100% food self-sufficiency and double as a very effective cover crop. I've written about this in detail before. As well, any extra or culls can easily be put into ethanol production with relatively high yields. The U'ala is a basic and reliable survival crop that with a years efforts can bring most any homestead in the area into near sustainable status.
They're good eats too.
You'll note above the sweet trick I'm giving away--the corrugated PVC roofing made into 12 foot hot houses. Perfect solution for my area building greenhouse space--bug, slug, vog and chicken proof for a 1 buck a square foot. I grow perfect greens in these and it makes my previously difficult crops flawlessly successful. It would be impossible to greenhouse for less money. Besides, you're growing in real soil so the flavor--and nutrition is much higher than anything one could possibly produce in a hydroponic situation. Here I am again, giving away a million dollar idea. . .ah well, what the hell. Beets, carrots, and spinich in those in the pictures, and the herb garden on the left.
God, I can grow some honking big sweet potatoes up here. . .that sucker in my hand must weigh 4 lbs.