Every distributor shall, within thirty days after each six-months’ period ending June thirtieth and December thirty-first, file with the fertilizer control board on forms supplied by the fertilizer control board a sworn certificate setting forth the information required by rule. At the time of filing said certificate, each distributor of fertilizer, excluding manipulated animal or vegetable manure, shall pay to the director the fee prescribed by rule, which fee shall not exceed one dollar per ton and one dollar ten cents per metric ton; except that, sales to fertilizer manufacturers or exchanges between them are hereby exempted. Each distributor of fertilizer consisting of manipulated animal or vegetable manure shall pay to the director a fee paid for each ton of manure as prescribed by rule, which fee shall not exceed two cents for each percent nitrogen for manure containing less than five percent nitrogen; or which fee shall not exceed four cents for each percent nitrogen for manure containing at least five but less than ten percent nitrogen; or which fee shall not exceed six cents for each percent nitrogen for manure containing ten or more percent nitrogen. In the event that the fertilizer control board has not prescribed a fee under this section, each distributor required to pay a fee under this section shall pay a fee of one and one-half cents for each one hundred pounds of fertilizer sold during the period covered by the certificate filed under this section. The director is hereby authorized to collect fees and hold all fees in a separate fund that shall be utilized by the fertilizer control board to administer sections 266.291 to 266.351.