Said boards of county commissioners are authorized, in addition to the authority granted in Kan. Stat. Ann. § 68-141a, to rent or hire to owners of land in the county for drought-relief purposes, county trucks, machinery and equipment, under supervision of its operators or employees and upon the agreement of said person to pay into the treasury of said county for credit to proper funds of said county, the amount charged for use of the equipment. All such unpaid amounts outstanding on September 1 of each year shall become a lien upon the entire contiguous tract of land owned by such person upon which said works were performed, and the county clerk shall spread upon the tax roll prepared by him, the balance of the amount due as shown by statement supplied by its operator, and the amount of said lien shall be collected as other taxes.