Land costs have increased dramaticly in my area over the past few years. 5 - 15K per acre isn't uncommon. The ratio is about 50:1 in terms of cost to productive value.

Farm land is taxed at 25% of residential but that can be adjusted if needed. There's some fear that a large portion of taxes will be shifted over to farmers because their land is worth so more, even though they require very little in terms of services from local government.
Not sure how it will play out. Farm land is rising in price faster than housing and it could stay that way for a while. This is also increasing the cost of rented land which is about 200.00 per acre on average.