Tenn. Code Ann. § 43-11-110

For the purpose of determining the commercial values to be applied under the provisions of § 43-11-109, the commissioner shall determine and publish annually the values per pound of nitrogen, available phosphoric acid, and soluble potash in commercial fertilizers in this state. If guarantees are as provided in § 43-11-103(9)(B), the values shall be per pound of nitrogen, phosphorus, and potassium. The values so determined and published shall be used in determining and assessing penalties.