Wisconsin Administrative Code
Department of Agriculture, Trade and Consumer Protection
ATCP 20-54 - Agricultural Resource Management
Chapter ATCP 40 - Fertilizer And Related Products
Subchapter II - Fertilizer
Section ATCP 40.10 - Fertilizer; guaranteed analysis

Universal Citation: WI Admin Code ยง ATCP 40.10

Current through August 26, 2024

(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:
1. That a fertilizer contains any plant nutrient unless that plant nutrient is identified in sub. (2) and in the guaranteed analysis under par. (a).

2. That a fertilizer contains the enhancing element cobalt or sodium unless that enhancing element is included in the guaranteed analysis under par. (a).

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 (K2O)

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:
1. Ready-to-use liquid fertilizer labeled only for nonagricultural uses.

2. Fertilizer labeled only for hydroponic or continuous plant feeding use.

3. Potting soil with nutrient guarantees.

4. Primary nutrient guarantees, authorized under s. ATCP 40.12(9), for fertilizer distributed pursuant to a permit under s. ATCP 40.12.

(c) Except as provided in sub. (6) (b) or (7), a fertilizer label may not identify any plant nutrient that has a guarantee of zero.

(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:
1. The sum of the guarantees for the primary plant nutrients is less than 24%.

2. The fertilizer is a fertilizer-additive combination.

3. The fertilizer label represents that the fertilizer contains an organic or slowly released plant nutrient.

(b) A plant nutrient source statement under par. (a) shall do all of the following:
1. Identify the source materials from which the guaranteed plant nutrients are derived, in descending order of content by weight of source material.

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.

(a) A zero shall precede the decimal point in every guarantee that is less than one percent.

(b) A minimum guarantee for a primary plant nutrient shall be stated as a whole number if the guarantee is at least 1.0%.

(6) CHEMICAL FORMS.

(a) If a guaranteed analysis identifies any chemical form of a plant nutrient that has more than one chemical form, it shall identify all chemical forms of the plant nutrient and provide a percentage guarantee for each. The percentage guarantee for each chemical form shall precede the identified chemical form and may include non-zero decimal units. Subsection (3) illustrates the correct format for nitrogen.

(b) A chemical form under par. (a) may have a percentage guarantee of zero, provided that the combined guarantee for all chemical forms of the plant nutrient equals or exceeds the minimum guarantee required under sub. (2).

(c) No person may represent that a fertilizer contains an organic or slowly released plant nutrient unless all of the following apply:
1. The guaranteed analysis lists slowly released chemical forms of that plant nutrient.

2. The combined guarantees for slowly released forms of the plant nutrient comprise at least 15% of the total guarantee for that plant nutrient, except as otherwise provided for nitrogen under sub. (8) (b).

(7) MAXIMUM GUARANTEES.

(a) A fertilizer label may contain a separate written statement, not part of the guaranteed analysis, which states that the amount of a specified plant nutrient or other substance does not exceed a specified percentage by weight of the fertilizer.

(b) No person may sell or distribute a fertilizer for use on tobacco unless its label states the maximum amount of chlorine that may be present in the fertilizer.

(8) NITROGEN GUARANTEES.

(a) A nonagricultural fertilizer label shall guarantee the ammoniacal, nitrate, water insoluble, and other chemical forms of nitrogen, as illustrated in sub. (3).

(b) No fertilizer label may identify nitrogen as organic unless the water insoluble or slow release nitrogen guarantee is at least 60% of the non-urea nitrogen designated as organic.

(9) PHOSPHITE AND PHOSPHOROUS ACID.

(a) Notwithstanding sub. (5) (a):
1. No fertilizer labeling may identify phosphite or phosphorous acid as a fertilizer ingredient.

2. No phosphate nutrient guarantee may include any phosphate derived from phosphite or phosphorous acid.

(b) Paragraph (a) does not prohibit the identification, in a fertilizer-pesticide combination, of a pesticide containing phosphite or phosphorous acid.

(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.

See definitions of "enhancing element" and "fertilizer-additive combination" in s. ATCP 40.02(7) and (9).

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