Notwithstanding any other provision of this Constitution, the legislature may hereafter, by general law, provide for the promotion of, the production, research, distribution, marketing, use, improvement and sale of swine and swine products. The legislature may provide for the promotion of swine and the swine industry by research, education, advertising and other methods, and the legislature is further authorized to provide means and methods for the financing of any such promotional activity by prescribing a procedure whereby producers of swine may by referendum held among the swine producers in this state levy upon themselves and collect assessments, fees, or charges upon the sale of swine for the financing of any promotional program or activity in cooperation with processors, dealers and handlers, of swine and swine products. Provided, no assessment levied hereunder shall exceed five cents (5¢) on market hogs and three cents (3¢) on feeder pigs sold by swine producers. The legislature may make provisions for the nonpayment of assessments by swine producers and shall make provisions for the refund of assessments to any swine producer dissatisfied with the assessment program. The legislature shall provide for the collection and distribution of any such assessments or charges by dealers, handlers, processors and purchasers of swine and swine products and provide penalties for failure to make collection and distribution of such assessments. The legislature shall provide for the designation of a nonprofit association or organization organized for the promotion and betterment of swine and swine products to administer and carry out such promotional program which shall include the conducting of elections or referendums among swine producers. The legislature may provide the manner by which such referendum is held, including the procedure for application for approval to conduct the referendum, the appropriate action to be taken by the state board of agriculture and industries on such application, the requirements and eligibility of the association or organization which will conduct such referendum, the procedures for voting and eligibility to vote in such referendum and the details of the conduct of such referendum. The legislature shall further provide for the deposit, withdrawal, disbursement and expenditure by the designated association of any funds received subject to the supervision and control of the activities as authorized herein by the department of agriculture and industries and the state board of agriculture and industries. The legislature shall further provide a procedure whereby said association or organization, and for reasonably necessary rules and regulations to be adopted by the state board of agriculture and industries to effectively carry out the intent and purposes herein enumerated. Assessments, fees or other charges collected as authorized by any legislative act adopted in pursuance hereof shall not be considered as a tax within the meaning of this Constitution or any provision thereof. Any uniformity requirements of this Constitution shall be satisfied by the application of the program upon swine and swine products.