The Missouri Soil Testing Association Accreditation Program (MSTA) is designed to assure that results provided by participating public and private labs serving the citizens of Missouri agree with allowable statistical limits. Based on this premise, soil test results from MSTA-approved labs will be accepted by the U.S. Department of Agriculture and Farm Service Agency (FSA). Beginning in 1999, MSTA combined its efforts with the North American Proficiency Testing Program (NAPT). The NAPT coordinator sends soil test data from the labs participating in MSTA program to the state coordinator. The MU Soil Testing Lab director serves as the state program coordinator and performs statistical analysis of the data as specified in the MSTA program. If a lab's results fall within the allowable limits, the lab will be placed on the Farm Service Agency's (FSA) list of approved labs. A lab that is not accredited may re-apply after one year.

See list of approved labs below.

Approval procedures for MSTA labs

The labs that wish to participate in the MSTA program should send a formal written request to the director of the MU Soil Testing Lab. They also need to request the NAPT coordinator to release their results to the MSTA program coordinator by signing a "Missouri Release" form when they sign up for NAPT.

Participating labs must use procedures of the Missouri Soil Testing Program in current use as described in the University of Missouri Extension Guide Soil Testing in Missouri (EC923).

The lab will be approved for routine soil tests:

  • Bray-I P; ammonium acetate extractable K, Ca, and Mg
  • Organic matter
  • pH in 0.01 M CaCl2
  • Neutralizable acidity (using the Woodruff Buffer test)

Standard pH 7.0 and pH 4.0 buffers must be used to calibrate all pH meters.

It is suggested each laboratory set up two or more internal check samples. One of these checks should be included with each twenty or thirty soil samples. A log of the results of the check samples should be maintained.

The MSTA coordinator will receive results from the NAPT program coordinator on the recommended tests and do the statistical evaluation.

Approval criteria for MSTA labs

The MSTA program uses the median and median absolute deviation (MAD) as used by the NAPT program as robust estimations of central values and variances of all data sets. This statistical approach is less sensitive to influence of extreme values (outliers) than the mean and standard deviation. The MSTA summary report lists the median and MAD values and the lab data. If the lab's data falls outside the range of +2.5x MAD (it is marked as Low or High) and considered to be out of the allowable limit. If the lab data falls outside the limits of +3.5x MAD they are marked as outliers.

Test results of 75 percent of the samples must fall within the above allowable limits for each test. Upon meeting these criteria a letter will be sent to FSA to add the requesting lab to the list of approved labs in Missouri. If a lab doesn't meet the criteria to be approved, contact the MU Soil Testing Lab director for a second chance for approval by analyzing five unknown samples sent by the MSTA program.

Missouri state approved labs

August 1, 2025 to July 31, 2026

Based on all four quarters of sample exchanges, 2024.

Missouri

  • Custom Ag Labs
    3068 State Highway 37
    Monett, MO 65708
    Phone: 417-553-8510
  • MU Soil and Plant Testing Lab
    University of Missouri
    23 Mumford Hall
    Columbia, MO 65211
    Phone: 573-882-3250
  • Perry Agricultural Lab
    PO Box 418
    15241 Pike 138
    Bowling Green, MO 63334
    Phone: 573-324-2931

Georgia

  • Waters Agricultural Lab
    257 Newton Hwy, PO Box 382
    Camilla, GA 31730
    Phone: 229-336-7216

Illinois

  • Waypoint Analytical Illinois, Inc.
    2902 Farber Rd
    Champaign, IL 61822
    Phone: 217-359-7680

Indiana

  • A&L Great Lakes Laboratory
    3505 Conestoga Drive
    Fort Wayne, IN 46808
    Phone: 260-483-4759

Iowa

  • AgSource Laboratories
    1701 Detroit Street, PO Box 247
    Ellsworth, IA 50075
    Phone: 515-836-4444
  • Waypoint Analytical Iowa, Inc.
    700 Park Drive
    Atlantic, IA 50022
    Phone: 712-243-6933

Kentucky

  • Waters Agricultural Laboratory
    2101 Old Calhoun Road, Hwy 81
    Owensboro, KY 42301
    Phone: 270-685-4039

Minnesota

  • MN Valley Testing Laboratories, Inc.
    1126 North Front St.
    New Ulm, MN 56073
    Phone: 507-354-8517

Nebraska

  • AgSource Laboratories
    300 Speedway Circle, Suite 2
    Lincoln, NE 68502
    Phone: 402-476-0300
  • American Agricultural Laboratory, Inc.
    700 W D Street
    McCook, NE 69001
    Phone: 308-345-3670
  • Midwest Laboratories, Inc.
    13611 B St.
    Omaha, NE 68144
    Phone: 402-334-7770
  • Ward Laboratories, Inc.
    4007 Cherry Ave.
    PO Box 788
    Kearney, NE 68848
    Phone: 308-234-2418

Ohio

  • Brookside Laboratories, Inc.
    200 White Mountain Drive
    New Bremen, OH 45869
    Phone: 419-977-2766
  • Spectrum Analytic, Inc.
    1087 Jamison Road NW
    Washington Court House, OH 43160
    Phone: 740-335-1562

Tennessee

  • Waypoint Analytical, Inc.
    2790 Whitten Road
    Memphis, TN 38133
    Phone: 901-213-2400

Wisconsin

  • AgSource Cooperative Services
    106 N. Cecil St.
    PO Box 788
    Bonduel, WI 54107
    Phone: 715-758-2178