Unless you're planning on opening up a business that requires the purchase of a property (boarding stable, farming, training, what have you), no bank would finance the purchase of a farm as part of a small business loan. Even then, most banks don't usually have enough experience with those types of businesses to know if they're going to be a decent investment.
There are a number of lenders that specialize ONLY in agricultural/rural property purchases. American AgCredit and AgChoice are two that specialize in those sort of lending practices.
If you're looking at opening up a business related to horses or farming, you're going to need to come up with a business plan before applying for a loan. This states what your goal is, where you expect to be in five years, and when the bank can expect a return on their investment.