Iowa R. Civ. P. 1.937
The order may specify or limit the master's powers or duties, the issue on which a report is to be made, or the time within which a hearing shall be held or a report filed, or specify that the master merely take and report evidence. Except as so limited the master shall have and exercise power to regulate all proceedings before the master; to administer oaths and to do all acts and take all measures appropriate for the efficient performance of the master's duties; to compel production before the master of any witness or party whom the master may examine, or of any evidence on any matters embraced in the reference, and to rule on admissibility of evidence. The master shall, on request, make a record of evidence offered and excluded. The master may appoint a shorthand reporter whose fees shall be advanced by the requesting party.
Iowa. R. Civ. P. 1.937