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

July 1, 2023 to June 30, 2024

Based on all four quarters of sample exchanges, 2022.


  • MU Soil and Plant Testing Lab
    University of Missouri
    23 Mumford Hall
    Columbia, MO 65211
    Phone: 573-882-3250
  • Custom Ag Labs
    3068 State Hwy 37
    Monett, MO 65708
    Phone: 417-553-8510
  • Perry Agricultural Lab
    PO Box 418
    State Highway 54 East
    Bowling Green, MO 63334
    Phone: 573-324-2931


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


  • Waypoint Analytical Illinois, Inc.
    2906 W. Clark Road
    Champaign, IL 61822
    Phone: 217-359-7680


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


  • Ag Source Laboratories
    1532 Dewitt
    Ellsworth, IA 50075
    Phone: 515-836-4444
  • Waypoint Analytical Iowa, Inc.
    111 Linn St.
    Atlantic, IA 50022
    Phone: 901-213-2400


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


  • MVTL Laboratories Inc. – New Ulm
    1126 North Front St.
    New Ulm, MN 56073-0249
    Phone: 507-354-8517


  • Midwest Laboratories, Inc.
    13611 B St.
    Omaha, NE 68144-3693
    Phone: 402-334-7770
  • Ward Laboratories
    4007 Cherry Ave.
    PO Box 788
    Kearney, NE 68848
    Phone: 308-234-2418
  • AgSource Laboratories
    300 Speedway Circle #2
    Lincoln, NE 68502
    Phone: 402-476-0300
  • American Agricultural Laboratory, Inc
    700 W. D St.
    McCook, NE 69001
    Phone: 308-345-3670


  • Brookside Laboratories, Inc.
    200 White Mountain Drive
    New Bremen, OH 45869
    Phone: 419-977-2766
  • Spectrum Analytical
    1087 Jamison Road
    PO Box 639
    Washington Court House, OH 43160
    Phone: 740-335-1562


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


  • Ag Source Cooperative Services
    106 N. Cecil St.
    PO Box 7
    Bonduel, WI 54107
    Phone: 715-758-2178