The Nebraska Dairy Industry Development Board is hereby created. Members of the board shall (1) be residents of Nebraska, (2) be at least twenty-one years of age, (3) have been actually engaged in the production of milk in this state for at least five years, and (4) derive a substantial portion of their income from the production of milk in Nebraska. Board members shall be nominated and appointed as provided in sections 2-3951.01 to 2-3951.04.