You quoted the price for beans, not corn. Corn averaged 3.40 over the year (currently, around $3.05 cash, not CBOT). That means it was about $640/acre for income. And that's assuming 203 bushels for all farmland. 180 is a better rule of thumb.
Of course, when a bag of seed corn is selling for $275-300+...not to mention input costs of equipment, fuel, fertilizer, labor (including yours), land (purchase or rent), etc...
The numbers were way better than I remembered, so I kept trying to figure out where the costs came in...I wasn't finding it.
Thanks for the correction.
As my late dad and other old timers said a few years ago, the price of land is tied to the price of corn. Land values (both purchase and cash rent) have fallen the past year or two from their high, slowly but steadily. From a pure numbers standpoint, land prices are still high relative to corn prices, I'd say about 2x as high as some historical years at this corn price (plus historical inflation). I'd like to see it down around $5K/acre in my area.
But there are other factors in the cost too, and that is how much people are willing to pay for land. And guys are still willing to pay for it at this level, although not as many as before. There's still profitability, if you play your cards right. But that's a whole other analysis.