Guideline Index

Chapter 8: Assessing Soil Nutrients

8.5 Soil and plant tissue testing laboratories

A number of laboratories throughout Australia offer a soil and plant testing service. Many laboratories have membership in the Australasian Soil and Plant Analysis Council (ASPAC), but only a limited number have membership of the National Association of Testing Authorities (NATA).

ASPAC conducts regular National Quality Assurance Programs to enhance standards of analysis and to provide standardisation of soil and plant analytical methods across laboratories. Those laboratories that produce analysis results that meet certain criteria are provided a ‘Certificate of Proficiency’ for each test in which they successfully participated. It is important to remember that ASPAC provides a proficiency certificate for individual tests, not on a whole-of-laboratory basis. Other tests that a laboratory carries out may not have been deemed sufficiently accurate to be worthy of a proficiency certificate. It is recommended that you ask the lab if they are certified for the tests that you require, or check on the ASPAC website (

ASPAC offers assistance to improve laboratory procedures. It also encourages laboratories to:

  • Use standard units for reporting so that results are comparable between laboratories.
  • Regularly check their testing techniques by testing samples with known values.
  • Use accredited methods that have been calibrated against field trials under local conditions.

NATA is an association that, among other duties, sets and maintains the high standard for the methodology of laboratory practices and technical advice and accredits laboratories. Laboratories with NATA accreditation are also required to participate in a quality assurance testing program such as ASPAC. More information about NATA is available at

Using a NATA accredited laboratory, or a laboratory with ASPAC proficiency certificates for the tests required, provides the best assurance of consistent and accurate test results. These laboratories are recommended over those that do not participate in recognised quality assurance programs.

Check the soil test methods offered have been calibrated for crops and pastures in your region or state. Test methods that haven’t been calibrated with research and trials are meaningless and should not be used.

Cost of analysis is also an important consideration but only laboratories with quality assurance should be considered when comparing costs.

Using the same quality assured laboratory for future analysis should provide greater consistency, and more comparable results.

Soil test results require interpretation. Check you are receiving quality advice. Fertcare provide quality assurance programs for advisors. For more information on Fertcare Accredited Advisors visit the Fertilizer Australia website: