Non-farming buyers don't really make any difference....they can buy it, but if they aren't going to farm it, then it's still in play for the existing operators in the area to farm. 

I don't really consider the buy/sell price of land to be relevant to farm operations.  The prevailing rental rate is the ruling factor for production decisions.  Land ownership is a mostly speculative endeavor unrelated to production ag. 

 If you are talking about existing farm operations buying land and farming it without regard to economics....well, there's not much you can do about that...if they have money then it's their right to buy whatever they want.  If they have millions of dollars laying around and no profit motive, then there's not much stopping them from doing whatever they feel like doing.   In order for economic law to apply, there has to be a profit motive of some sort.   See my tag line: