Rentals.

All leases issued by the commissioner shall provide for an annual rental to be paid by the lessee in advance, the amount thereof to be fixed by the commissioner, but in no case shall the same be less than five cents (5¢) per acre for the primary term nor less than fifty cents (50¢) per acre for the secondary term; provided that the annual rental for any one lease shall not be less than ten dollars ($10.00).