In the manner set forth in this chapter and under regulations as established under the provisions of this chapter there must be held in every county in the State in which flue-cured tobacco is produced a referendum to be participated in by all farmers engaged in the production of flue-cured tobacco. Those farmers entitled to share in the crop of flue-cured tobacco or in the proceeds of the crop because of sharing in the risk of production are considered to be engaged in the production of flue-cured tobacco. In the referendum individuals eligible for participation shall vote upon the question of whether or not there must be levied an annual assessment for a period of three years in an amount not to exceed ten dollars an acre on all tobacco acreage, the exact amount an acre to be determined by the members of the board of directors of Tobacco Associates, Incorporated, subject to the approval of the majority of the South Carolina members of the board of directors, or in an amount not to exceed fifty cents for each one hundred pounds of the flue-cured tobacco marketed by each farmer under the alternate method for assessment provided for in § 46-31-140.