If the complaint in an action to foreclose on agricultural land of more than forty acres [16.19 hectares] has provided for a deficiency judgment, a separate action for the deficiency must be brought within ninety days after the sheriff’s sale. In the separate action, a deficiency judgment may be entered, but may not be in excess of the amount by which the sum adjudged to be due and the costs of the action exceed the fair market value of the mortgaged premises. There is not a presumption that the premises sold for the fair market value. The court may not render a deficiency judgment unless the fair market value as determined by the court is less than the sum adjudged to be due and costs of the action. Fifteen days’ notice of the time and place for determination of fair market value must be given to all parties against whom personal judgment is sought. Any party may offer evidence to show the fair market value even though that party may not have otherwise appeared in the action for a deficiency judgment. Any deficiency judgment obtained may only be enforced by execution within three years from the date of entry of the judgment. If the judgment is not collected within three years, the judgment expires. As used in this section, “fair market value” means the most probable price that real property can be sold for in the open market by a willing seller to a willing buyer, neither acting under compulsion and both exercising reasonable judgment.