Missouri Soil Testing Approval Program.

The Missouri Soil Testing Association (MSTA) approval program was started in mid 80s to ensure the soil testing labs that serves the citizens of Missouri provide reliable and quality test results. This program was designed to assure that results provided by participating public and private labs serving in Missouri agree within the allowable statistical limits. This was accomplished by evaluating the soil testing laboratories in their performance through inter-laboratory sample exchanges and a statistical evaluation of the analytical data. Based on this premise, soil test results from MSTA approved labs will be accepted by the U.S. Department of Agriculture, Farm Service Agency (FSA) and Department of Natural Resources and Conservation Services (NRCS) in federally assisted cost share programs and nutrient management plans in the state of Missouri. Till 1998 the MSTA Coordinator sent out four unknown samples for each quarter to the participating lab for analysis. The labs were requested to provide results for the tests required by the MSTA: pHs (1:1 0.01 M CaCl2), Modified Woodruff buffer pH, Bray 1 P, Ammonium Acetate Extractable K, Ca, Mg, soil OM (Loss on Ignition or Walkley Black). The labs were approved based on their performance following the criteria set by the MSTA program. http://soilplantlab.missouri.edu/soil/msta.aspx. In 1999 the Missouri State program joined the North American Proficiency testing Program (NAPT) and worked in collaboration with the NAPT. To be approved by the MSTA, the participating labs should participate in all four quarter exchanges of the NAPT, and provide results for tests required by MSTA. The NAPT Coordinator forwards the test results for the labs to the MSTA Coordinator. 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.