Mo. Rev. Stat. § 266.525: Quality standards for agricultural liming materials.

All agricultural liming materials offered for sale must be capable of correcting soil acidity, and furnishing calcium or magnesium, as plant nutrients, and meet the minimum specifications for calcium carbonate equivalent, and fineness of grind, as set forth in the regulations. All agricultural liming materials offered or exposed for sale in Missouri shall guarantee the pounds of effective magnesium per ton and the pounds of effective neutralizing material per ton. Effective magnesium and effective neutralizing material shall be calculated by the methods set forth in the regulations according to the percentage of magnesium, the calcium carbonate equivalent and fineness as determined in section 266.535.