Wis. Admin. Code § ATCP 40.10
(1) General.
(a) A fertilizer label shall contain a guaranteed analysis that complies with this section. A guaranteed analysis may guarantee any plant nutrients or enhancing elements identified in sub. (2), and shall guarantee at least one of the plant nutrients identified in sub. (2). Each guarantee shall be expressed as a minimum guaranteed percentage by weight of the fertilizer.
Note: All of the materials identified in sub. (2), except cobalt and sodium, are plant nutrients. Cobalt and sodium are “enhancing elements.” See ATCP 40.02 (7).
(b) No person may represent any of the following:
3. That a fertilizer contains an enhancing element other than cobalt or sodium, unless that enhancing element is guaranteed as a soil or plant additive ingredient under sub. (10).
Note: A fertilizer that claims enhancing elements, other than cobalt and sodium, is considered a “fertilizer-additive combination.” See ATCP 40.02 (9).
(2) Minimum guarantees.
(a) Except as provided in par. (b), no person may represent that a fertilizer contains any of the following plant nutrients or enhancing elements unless that plant nutrient or enhancing element is guaranteed at or above the following amount:
Plant Nutrient Minimum Guarantee
Total Nitrogen (N) 1.0%
Available Phosphate (P2O5) 1.0%
Soluble Potash (K20) 1.0%
Calcium (Ca) 1.0%
Magnesium (Mg) 0.5%
Sulfur (S) 1.0%
Boron (B) 0.02%
Chlorine (Cl) 0.1%
Cobalt (Co) 0.0005%
Copper (Cu) 0.05%
Iron (Fe) 0.1%
Manganese (Mn) 0.05%
Molybdenum (Mo) 0.0005%
Nickel (Ni) 0.05%
Sodium (Na) 0.1%
Zinc (Zn) 0.05%
(b) Paragraph (a) does not apply to any of the following:
(3) Format. A guaranteed analysis shall appear in the following format:
Guaranteed Analysis
Total Nitrogen (N) ___%
_____% Ammoniacal Nitrogen
_____% Nitrate Nitrogen
_____% Water Insoluble Nitrogen
_____% (Other recognized and determinable forms of nitrogen)
Available Phosphate (P2O5) ___%
Soluble Potash (K2O) ___%
Calcium (Ca) ___%
Magnesium (Mg) ___%
Sulfur (S) ___%
Boron (B) ___%
Chlorine (Cl) ___%
Cobalt (Co) ___%
Copper (Cu) ___%
Iron (Fe) ___%
Manganese (Mn) ___%
Molybdenum (Mo) ___%
Nickel (Ni) ___%
Sodium (Na) ___%
Zinc (Zn) ___%
Note: Percentage guarantees must equal or exceed the minimum guarantees specified in sub. (2).
(4) Nutrient source statement.
(a) A guaranteed analysis shall include a separate nutrient source statement if any of the following apply:
(b) A plant nutrient source statement under par. (a) shall do all of the following:
2. Identify the source of each plant nutrient, using only terms defined in the Official Publication of the Association of American Plant Food Control Officials, No. 71 (2018).
Note: The Official Publication of the Association of American Plant Food Control Officials, No. 71 (2018) is on file with the department and the legislative reference bureau. Copies may be obtained from the treasurer of the Association of American Plant Food Control Officials, Inc., North Carolina Department of Agriculture, P.O. Box 33508, Raleigh, NC 33636-3508, or online at http://www.aapfco.org.
(5) Percentage guarantees; how expressed.
(6) Chemical forms.
(c) No person may represent that a fertilizer contains an organic or slowly released plant nutrient unless all of the following apply:
(7) Maximum guarantees.
(8) Nitrogen guarantees.
(9) Phosphite and phosphorous acid.
(a) Notwithstanding sub. (5) (a):
(10) Fertilizer-additive combinations. The guaranteed analysis for a fertilizer-additive combination shall be in the format shown in Appendix A. Enhancing nutrients other than cobalt and sodium, if claimed, shall be guaranteed as soil or plant additive active ingredients.
Note: See definitions of “enhancing element” and “fertilizer-additive combination” in s. ATCP 40.02 (7) and (9).
History: CR 04-140: cr. Register September 2005 No. 597, eff. 10-1-05; CR 14-047: am. (4) (b) 2. Register May 2015 No. 713, eff. 6-1-15; CR 16-012: am. (4) (b) 2. Register August 2016 No. 728, eff. 9-1-16; CR 18-019: am. (4) (b) 2. Register January 2020 No. 769, eff. 2-1-20.