All lands directly benefitted by any irrigation or drainage project, or any irrigation or drainage works established under this chapter, and all public or corporate roads or railroads so benefitted in whole or in part, shall be assessed in proportion to the benefits for the construction thereof. All lands owned by the state of Idaho benefitted by such project may be assessed for such benefit the same as taxable land, provided a notice of the filing of the petition and of the time and place of hearing and notice of hearing shall have first been served on the state agency responsible for the management of such state owned lands: provided, that instead of paying the said assessments so levied against the state lands, the state may promptly offer said state lands for sale at public sale in the manner provided by law, and as rapidly as permitted by the provisions of the state constitution, until the entire acreage of state land in such project shall have been sold and if the state does not make appropriations for the payment of such assessments against such state lands, then the sale of such state land, when made, shall be made under contract requiring the purchaser as a condition to receiving title to such lands from the state, or to receiving any contract right or interest therein, to pay all assessments duly levied against such lands under the provisions of this chapter, and to pay to the proper county officer at the time of such sale such annual assessments as may have come due prior to the time of such sale, with interest thereon as hereinafter provided, and to continue the payment of such assessments until title passes from the state to such purchaser, which conveyance shall be made from the state to the purchaser subject to the liens herein provided for.