Iowa Code § 458A.24
If a recorded lease contains the statement of any contingency upon the happening of which the term of any such lease may be extended, the owner of said lease may at any time before the expiration of the definite term of said lease file with said county recorder an affidavit setting forth the description of the lease, that the affiant is the owner thereof and the facts showing that the required contingency has happened, or the record of such lease shall not impart notice to the public of the continuance of said lease. This affidavit shall be recorded in full by the county recorder and such record together with that of the lease shall be due notice to the public of the existence and continuing validity of said lease, until the same shall be forfeited, canceled, set aside, or surrendered according to law.
Iowa Code § 458A.24
Referred to in §331.602