Well, there`s alot of factors a couple years ago when any soil that would hold up a plant was bringing $13,000/acre, every fall it appeared you`d sell +$6 corn off the combine and 3% land money was abundant...all those factors had to be in place to support those land prices. And at that time who knew? Corn could`ve hit a new $10 price plateau, interest probably couldn`t have been expected to have gotten any cheaper than 3%. But $13,000 is high priced by anyone`s yardstick, it was probably 4 times higher than any of us had heard, while corn was just double a "good price" ...20/20 hindsight, land shouldn`t have gotten above $7,000.
That cheap money and the promise that the world population will be 9 billion by 2050 and now farming is fun probably created irrational exuberance by twice on land prices. There`s herd mentality among farmers, all it takes is one nut to try combining green beans and then everybody else has to try it, even though it makes absolutely no sense 
In the 80`s, I really thought as badly as farmers were burnt it would destory their risk taking gene. But their memories were pretty short and it was off to the races before the end of the decade. Of course even with bargain land prices in the 80`s and 90`s money was high priced and hard to get. Those sweet spots of cheap money and low land prices are very rare, probably during those times grain prices are low and off farm income will be needed to make the farm payments.
What`s different today is some farmers own +1,000 acres and if they desire to buy a quarter, they have enough horsepower in reserve that they can easily over pay on a single parcel.
Two factors
Cheap interest....
And there is nowhere else to find an investment that matches it. cheap interest
price of land may get cheaper, but not dirt cheap
