Wisconsin Administrative Code
Department of Agriculture, Trade and Consumer Protection
ATCP 20-54 - Agricultural Resource Management
Chapter ATCP 50 - Soil And Water Resource Management Program
Subchapter VI - Soil and Water Professionals
Section ATCP 50.50 - Soil and manure testing laboratories

Universal Citation: WI Admin Code § ATCP 50.50

Current through May 27, 2025

(1) CERTIFIED LABORATORY. A nutrient management plan shall be based on soil tests conducted at the University of Wisconsin or another soil testing laboratory certified by the department. The department may certify a laboratory according to this section.

(2) APPLYING FOR CERTIFICATION. A laboratory operator may apply to the department for certification under sub. (1). An operator shall submit a separate application, on a form provided by the department, for each laboratory for which the operator seeks certification. The application shall include all of the following:

(a) The name of the laboratory operator.

(b) The address of the laboratory.

(c) The name and telephone number of the individual who is responsible for on-site administration of the laboratory.

(d) The soil tests, test methods, and nitrogen estimation methods used by the laboratory. The laboratory shall be capable of performing the following tests according to methods prescribed by the University of Wisconsin-Extension in Nutrient Application Guidelines for Field, Vegetable, and Fruit Crops in Wisconsin, UWEX Publication A2809 (2012), and by the University of Wisconsin-Madison soil science department in Wisconsin Procedures for Soil Testing, Plant Analysis and Feed & Forage Analysis, Soil Fertility Series (October, 2013) and shall be capable of estimating nitrogen levels based on those tests:
1. Soil pH.

2. Buffer pH.

3. Phosphorus (P).

4. Potassium (K).

5. Organic matter (OM).

Note: Copies of the Nutrient Application Guidelines for Field, Vegetable, and Fruit Crops in Wisconsin. UWEX Publication A2809 (2012) and the Wisconsin Procedures for Soil Testing, Plant Analysis and Feed & Forage Analysis, Soil Fertility Series (October, 2013) are on file at the department and legislative reference bureau. To obtain a copy of the A2809, see s. ATCP 50.04 (3) (f) 4. (note). Copies of the Wisconsin Procedures publication are available at the University of Wisconsin website at: https://uwlab.soils.wisc.edu/about-us/lab-procedures-and-methods/.

(e) Documentation showing that the laboratory is qualified and equipped to perform accurate soil tests and nitrogen estimates under par. (d).

(f) License conditions specified by the department, including compliance with subs. (4) to (6).

(g) Other relevant information required by the department.

Note: The soil testing laboratory certification form and the list of approved soil testing laboratories can be found at the following web address: https://datcp.wi.gov/Pages/Programs_Services/ATCP50.aspx.

(3) ACTION ON CERTIFICATION REQUEST. The department shall grant or deny a certification request under sub. (2) within 30 days after the department receives a complete request. The department may grant a certification request based on information provided under sub. (2). A certification is nontransferable. A certification remains in effect until withdrawn by the department.

(4) NUTRIENT RECOMMENDATIONS. If a certified laboratory recommends nutrient applications to a landowner that exceed the amounts required to achieve applicable crop fertility levels recommended by the University of Wisconsin Extension in Nutrient Application Guidelines for Field, Vegetable and Fruit Crops in Wisconsin, UWEX publication A2809 (2012), the laboratory shall make those recommendations in writing and shall disclose all of the following in the same document:

(a) The landowner's name and address.

(b) The nutrient application amounts required to achieve applicable crop fertility levels recommended by the University of Wisconsin-Extension. The laboratory shall disclose these amounts so the landowner can easily compare them with the laboratory's recommended amounts.

(c) The following statement, clearly and conspicuously printed adjacent to the laboratory's recommended nutrient applications:

IMPORTANT NOTICE

Our recommended nutrient applications exceed the amounts required to achieve applicable crop fertility levels recommended by the University of Wisconsin. The amounts required to achieve the UW's recommended crop fertility levels are shown for comparison. Excessive nutrient applications may increase your costs, and may cause surface water and groundwater pollution. If you apply nutrients at the rates we recommend, you will not comply with state soil and water conservation standards. You may contact your county land conservation committee for more information.

Note:To obtain a copy of A2809, see s. ATCP 50.04 (3) (f) 4. (Note).

(5) RECORDS. A certified soil testing laboratory shall keep records of all of the following for at least 4 years, and shall make those records available for inspection and copying by the department upon request:

(a) Records of all soil tests conducted at the laboratory.

(b) Copies of all nutrient application recommendations made by the laboratory.

(6) LABORATORY EVALUATION.

(a) The department or its agent may review the performance of a soil testing laboratory certified under this section. The department or its agent may do any of the following as part of its review:
1. Review relevant laboratory records.

2. Evaluate laboratory facilities and methods.

3. Evaluate the proficiency of laboratory analysts.

4. Evaluate the laboratory's proficiency in testing check samples provided by the department or its agent.

(b) A laboratory operator shall cooperate with a reasonable review under par. (a).

(7) DENYING OR WITHDRAWING CERTIFICATION.

(a) The department may deny, suspend, revoke, or impose conditions on a certification under this section if the department finds that the laboratory has done any of the following:
1. Failed to submit a complete application under sub. (2).

2. Failed to perform soil tests with reasonable accuracy.

3. Failed to comply with applicable requirements under this section.

4. Falsified relevant information.

(b) If the department denies, suspends, revokes, or imposes conditions on a laboratory certification, the department shall give the laboratory operator written notice of the department's reasons for that action.

(c) A laboratory operator may request a contested case hearing under s. 227.42, Stats. and ch. ATCP 1 on the department's action under this subsection.

(8) MANURE TESTING LABORATORIES. Manure nutrient values determined by laboratory analyses do not qualify under s. ATCP 50.04 (3) (dm) 2. unless the laboratory performing those analyses complies with all of the following:

(a) The laboratory participates in the manure analysis proficiency program administered by the Minnesota department of agriculture, or in an equivalent proficiency program administered by the University of Wisconsin soil analysis laboratory, and provides copies of proficiency reports to the department upon request.

Note: A manure testing laboratory may qualify under sub. (8), regardless of whether the laboratory is certified as a soil testing laboratory under sub. (1). A laboratory may contact the department, at the following address, for information on how to enroll in a manure analysis proficiency program under par. (a):

Wis. Department of Agriculture, Trade and Consumer Protection

Agricultural Resource Management Division

Nutrient Management Program

PO Box 8911

Madison, WI 53708-8911

(b) The laboratory is capable of performing all of the following manure analyses according to methods prescribed by the University of Wisconsin-Extension in Recommended Methods of Manure Analysis, UWEX publication A3769 (2003):
1. Percent dry matter (DM).

2. Total nitrogen.

3. Total phosphorus expressed as P 20 5.

4. Total potassium expressed as K 20.

Note: The University of Wisconsin-Extension publication, Recommended Methods of Manure Analysis, UWEX publication A3769 (2003), is on file with the department and legislative reference bureau. Copies may be obtained by visiting the UWEX website at: http://learningstore.uwex.edu.

(c) The laboratory is capable of estimating total and available nutrient levels based on the manure tests under par. (b) and the availability percentages shown in Nutrient Application Guidelines for Field, Vegetable and Fruit Crops in Wisconsin, UWEX publication A2809 (2012).

(9) CONFLICT OF INTEREST. For the purpose of complying with s. ATCP 50.04 (3) a privately owned laboratory certified under this section shall not perform soil test analysis on cropland managed or owned by a person managing or having a substantial financial interest in the laboratory.

To obtain copies of the NRCS technical guide nutrient management standard 590 (September, 2005) and the Wisconsin conservation planning technical note WI-1, see s. ATCP 50.04(3) (dm) 1. (Note).

Disclaimer: These regulations may not be the most recent version. Wisconsin may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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