Section 68. There shall be paid to the commissioner for all commercial fertilizers, soil conditioners, and agricultural liming materials distributed in the commonwealth, an inspection fee, set by the commissioner in rules and regulations; provided, however, that sales to manufacturers or exchanges between manufacturers are exempted from said fee on individual packages of commercial fertilizer and agricultural liming materials containing ten pounds or less.

In lieu of the annual registration fee of twenty-five dollars per brand and grade and the prescribed inspection fee there shall be paid on individual packages of specialty fertilizers containing ten pounds or less an annual registration fee and inspection fee of twenty-five dollars for each brand and grade sold or distributed. If specialty fertilizer is sold in packages of ten pounds or less, and in packages of over ten pounds, the annual registration and inspection fee of twenty-five dollars shall apply only to that portion sold in packages of ten pounds or less, and the portion sold in packages of over ten pounds shall be subject to the prescribed inspection fee.

If more than one person is involved in the distribution of a commercial fertilizer, soil conditioner, or agricultural liming material, the last person in possession before distribution to a nonlicensee or to a nonregistrant shall be responsible for reporting the tonnage and paying the inspection fee, unless the report and payment has been made by a prior distributor.