ELLSWORTH, Iowa – Accurate data leads to accurate decisions, which means higher yields and more profit. But how can you know your ag testing lab is giving you accurate results?
Most states require labs doing soil, plant tissue and manure testing be certified. The certification process involves performance testing that verifies a lab’s accuracy, according to Dr. Jim Friedericks, AgSource Laboratories’ Outreach and Education Advisor.
It is important to have your ag lab be certified by North American Proficiency Testing (NAPT) and/or Agricultural Laboratory Proficiency Program (ALP), he said. You should be able to find this information on your lab’s website, said Friedericks. Both NAPT and ALP submit reference samples to laboratories on a quarterly base for analysis. Laboratory results from the participating laboratory are then compared with data from all of the participating laboratories.
Many state agriculture departments use these programs to determine laboratory accuracy for approving laboratory certification. Both programs manage soil, plant and irrigation water samples and are operated by a third party, non-profit association.
There are a number of methods validated by university research used in soil testing. Agronomy experts in various regions of the United States meet regularly to discuss the latest research to set standards for quality testing.
Use the following “Quick Quality Questions” as a simple, effective way to judge the accuracy of your testing laboratory.
- Which proficiency testing programs do you participate in?
- What are the processes and procedures in place to ensure accuracy?
- Is your laboratory staffed with full-time employees, 52 weeks per year? What proportion of your staff are employed full-time, year round?
- How is data transferred from instruments to the reporting system and to the client?
It is also good to know what your lab does to insure both quality and accuracy. Accuracy is achieved by following appropriate methods and confirmed by using multiple checks of a method. Some of these performance checks are internal and some are external, ‘blind’, performance samples. The precision in a lab is the ability to get consistent results on the same test. Precision is achieved by carefully following a method and using instrumentation that is well maintained and properly calibrated.
Your laboratory should maintain complete records of all supporting quality control (QC) data for each report item. The aim of this program is simple: To provide error-free, substantiated, analytical data of precision and accuracy, governed solely by instrumental limitations.
Find a lab you like working with and are familiar with and stick with it, Friedericks recommended. “It is important to be consistent over time. But, if a lab suddenly gives you test results that are unexpected, ask them to re-run the test for you to confirm results.”
Friedericks said your lab should have someone involved with the testing process available to answer questions and help interpret the data if needed. He also notes it is often best to have one lab do all of your testing. For example, a manure management plan requires testing the manure and the soil and using the data from both in the plan. Some labs offer a volume discount if all testing is done through the same labs.
AgSource Laboratories is one of the certified labs serving the midwest, which utilize a rigorous quality control (QC) program supported by an experienced and dedicated analytical team.
The AgSource laboratory in Ellsworth is the newest facility in the AgSource group of labs. AgSource has labs in Bonduel, Wis., Lincoln, Neb., Ellsworth, Iowa, Umatilla, Ore., and a Food and Environmental lab in Marshfield, Wis.
AgSource is a leader in agricultural and environmental laboratory analysis and information management services. A division of Cooperative Resources International, AgSource Laboratories provides testing services to clients in the United States and across the globe. Learn more at www.agsource.com/laboratories.
— AgSource Cooperative Services
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