Section, act Feb. 16, 1938, ch. 30, title III, 315, as added Aug. 21, 1958, Pub. L. 85–705, 72 Stat. 703, provided for a referendum among producers of type 21 (Virginia) fire-cured tobacco and type 37 Virginia sun-cured tobacco on the question of a single combined tobacco acreage allotment and provided for establishment and subsequent increases and decreases in allotments.