When they shall deem it necessary, in order to preserve the value of such property, or its rental value, administrators, administrators with will annexed and executors of deceased persons, and guardians of minors or incompetent persons may lease or extend existing leases as to business property, or property to be improved for business purposes, or property used for wind energy conversion, belonging to the estate of said deceased persons, minor or incompetent person, for a term of not more than fifteen (15) years, with the approval of the district court administering said estate of such deceased person, or minor or incompetent person. In order to obtain said approval said administrator, administrator with will annexed, executor or guardian shall file in said district court a petition setting out the general nature of the property desired to be leased, or upon which the lease is desired to be extended, and the facts relative to the necessity of such lease for the preservation of the value of said property, or its rental value. The heirs, devisees and legatees of said deceased person and the next of kin of said minor or incompetent person are designated as persons interested in the estate and are entitled to be heard with respect to such proposed leasing. Provided, if the will of such deceased person shall authorize the executor or administrator with will annexed to sell the property of said decedent such authority shall be considered to include and extend the power to lease said property and further compliance with this act¹ shall not be necessary.