Iowa Code § 639.46: Appraisement.

To determine the value of property in cases where a bond is to be given, unless the parties agree otherwise, the sheriff shall summon two disinterested persons having the qualification of jurors, who, after having been sworn by the sheriff to make the appraisement faithfully and impartially, shall proceed to the discharge of their duty. If such persons disagree as to the value of the property, the sheriff shall decide between them.