Notwithstanding other laws to the contrary, in the event a commodity or marketing agreement or marketing order under the jurisdiction of the United States Department of Agriculture or other appropriate federal agency, is created by referendum or under the applicable laws and procedures relating thereto, in this state or in any geographical area within this state, which agreement or order contains provisions substantially similar to the provisions of this chapter, this chapter shall be inapplicable to any producer, shipper, or other person covered by, and, to the extent of such coverage, during the existence of such federal agreement or order.