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Lab certification ensures farmers receive accurate manure analysis reports.

Paula Mohr, Editor, The Farmer

September 1, 2022

2 Min Read
fecal matter sample in glass container waiting to be tested
TEST AND KNOW: Having a certified lab test livestock manure samples from your farm ensures that appropriate manure nutrients and amounts will be applied to cropland.Sinhyu/Getty Images

The only manure analysis proficiency testing program in North America has its roots in Minnesota.

The Minnesota Department of Agriculture’s Manure Analysis Proficient (MAP) program began in 1996 to ensure lab accuracy and credibility of manure test results. Fourteen labs participated that first year. Today, 54 laboratories in the U.S. and Canada are in the program.

Larry Gunderson, MDA Pesticide and Fertilizer Management Division, says the program helps provide accurate nutrient information to farmers about their livestock manure. Nutrient management education, cost-share and regulatory programs over the last 10-plus years prompted more livestock producers to seek manure testing. For example, according to the Minnesota Pollution Control Agency’s feedlot permitting rules, farms with more than 100 animal units are required to test manure at least once every four years. And use of an MDA-certified laboratory is required by the Minnesota Natural Resources Conservation Service for Environmental Quality Incentives Program-funded nutrient management plans.

The ag lab testing industry has been supportive of the MDA certification program from the start. Lab staffs say increased customer demand, the need to fill information gaps and the desire to promote the value of manure testing have prompted them to invest more resources in manure testing and nutrient management services.

Labs in the MAP program are sent unknown manure samples twice a year to test, Gunderson says, and then the labs return their test results to MDA. Those that pass are eligible for certification, and most labs have taken that additional step. All labs are certified in analyzing for nitrogen and phosphorus. Some are certified for other tests including potassium, solids, electrical conductivity, copper, sulfur and zinc.

Certified laboratories now analyze most manure samples tested in the Midwest.

Gunderson says MDA used to handle samples in-house, but now the agency contracts with Central Lakes College in Staples, Minn., to collect, mix and ship manure samples to the labs.

To learn more about MAP, visit



About the Author(s)

Paula Mohr

Editor, The Farmer

Mohr is former editor of The Farmer.

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