John Breker Appointed to NAPT Oversight Committee

This article originally appeared in the AGVISE Laboratories Spring 2023 Newsletter

John Breker was appointed to the North American Proficiency Testing Program Oversight Committee as the North Central Region representative, starting in January 2023. The North American Proficiency Testing (NAPT) Program assists soil, plant, and water laboratories with quality control and quality assurance through inter-laboratory sample exchanges as well as statistical evaluation of the analytical data. These tools help laboratories generate accurate and precise analyses, as well as provide confidence to clients that their data meets high standards.

The NAPT program guidelines have been developed for the agricultural laboratory industry by groups involved with standardizing soil and plant analysis methods in the United States and Canada. The program is authorized through the Soil Science Society of America (SSSA) and administered by the NAPT Oversight Committee, composed of representatives from regional soil and plant analysis workgroups, state/provincial departments of agriculture, and private and public soil and plant analysis laboratories.

AGVISE Laboratories has been a member of the NAPT program since its inception. AGVISE Laboratories in Benson, MN and Northwood, ND participate in the soil, plant, and water programs through NAPT, as well as the Performance Assessment Program (PAP) required for participation in USDA-NRCS programs. AGVISE is a strong supporter of NAPT and the ongoing objectives of the NAPT program.

NAPT Program Objectives

  • Provide an external quality assurance program for agricultural laboratories
  • Develop a framework for long-term improvement of quality assurance for the agricultural laboratory industry
  • Identify the variability of specific methods



Quality Control is First Priority for AGVISE

When you receive a soil test report from AGVISE you should expect the best. Since our start in 1976, our first priority has been providing you with the most accurate soil test data. Ensuring proper quality control and quality assurance (QC/QA) takes extra care and dedication from everyone at AGVISE to provide you with the best data possible.

for quality control article

Quality control in sample identification

Quality control in soil testing begins with a unique reference number/barcode on every sample bag. AGVISE will never ask you to write information on your soil sample bags. Deciphering unreadable handwriting is the first place mistakes happen. With the barcoded reference number on each sample bag, we track samples from the moment they arrive, through the analysis process, and when results are entered into AGVISOR, our online soil reporting system. AGVISE has used barcode reference numbers to identify soil samples for over 30 years. Since 2010, we have also offered online soil sample submission. The online submission system is another way to reduce errors because the customer can send the correct data directly to the laboratory. With online submission, there is no worry of misreading handwritten information!

When your soil samples arrive, we scan the barcode sticker and record its unique reference number, confirming it has reached the laboratory. Soil samples are dried overnight and ground the next morning. It is important to homogenize the soil sample through grinding and blending to ensure that what is analyzed represents the entire field, zone, or grid that was sampled.

Quality control in the laboratory

Soil analysis requires skilled technicians and calibrated instrumentation.  Each soil analysis is done following accepted methods for soils in our region and supported by university soil test calibration research.  When a soil test is performed (e.g. nitrate-nitrogen), quality control samples or “check samples” are tested along with customer samples to ensure accuracy and precision. The “check soil” has verified nutrient levels so we know what test value to expect every time. If a check soil value is outside the accepted range, all analysis from that group of samples is retested after the issue is corrected.  A check soil is tested after every ten customer samples. Therefore, ten percent of all soil tests done in the laboratory each day are quality control samples!  This past year, AGVISE used over 2,000 pounds of check soil in our quality control program to ensure you are receiving accurate data to make soil fertility decisions with.

Quality control – Laboratory proficiency and certification programs

AGVISE Laboratories in Northwood, ND and Benson, MN participate in three proficiency testing programs: the National Proficiency Testing program (NAPT), the Agriculture Laboratory Proficiency (ALP) program, and the Minnesota Department of Agriculture Manure Analysis Proficiency program. Our laboratories are also approved by the NAPT-Performance Assessment Program (PAP) and are certified soil and manure testing laboratories by the Minnesota Department of Agriculture. The Benson, MN laboratory is also an Iowa Department of Agriculture certified soil testing laboratory.

The proficiency programs send double-blind samples throughout the year to AGVISE. The samples are tested and results are evaluated by the proficiency programs for accuracy. Approval from PAP means that AGIVSE uses PAP approved methods to conduct soil analyses, which are required for NRCS programs. AGVISE has been involved with the NAPT proficiency testing program since it started in 1983.  As a longtime participant, AGVISE has had committee representatives on the NAPT Oversight Board for many years, striving to make the program better each year.

Quality control has been and will continue to be a priority for AGVISE Laboratories. When you receive a soil test report from AGVISE, you can be sure you are receiving the most accurate data possible.

More information about soil test certification and proficiency programs:

Agricultural Laboratory Proficiency Program (ALP)

Iowa Department of Agriculture Certified Soil Testing Laboratories

Minnesota Department of Agriculture Certified Manure Testing Laboratories

Minnesota Department of Agriculture Certified Soil Testing Laboratories

North American Proficiency Testing Program (NAPT)

Performance Assessment Program (PAP)