Initiatives of the Australasian Soil and Plant Analysis Council to Assess the Measurement Quality of Common Methods for Soil and Plant Analysis in Australasia

Abstract

The Australasian Soil and Plant Analysis Council Inc (ASPAC) commenced its not‐for‐profit interlaboratory proficiency programs (ILPPs) in 1990 and issued its first soil program report in 1993. ILPPs target soil and plant chemical testing laboratories across Australasia. These ILPPs contribute to ASPAC's goals to promote excellence in all aspects of soil and plant analysis and to encourage adoption of preferred methods and protocols used in soil and plant analysis within Australasia. The ASPAC recently re‐engineered its ILPPs to increase both their frequency and the number of samples assessed in a program year, the first of which was completed in 2004–5. This article provides more details on these new ILLPs for soils and plants, including how ASPAC's method‐specific certification now operates. More than 35 laboratories undertake the most popular soil tests but less than half report results for more specialized or less common tests. Also included is an outline of comparative results from a pilot assessment of Mehlich 3 soil‐test parameters using four homogeneous samples (and results) obtained from the North American ILPP. For the most part, results were wider apart than expected, which may be confounded by storage and handling changes in the samples that also had to pass strict quarantine protocols in Australia and New Zealand. The ILPPs of ASPAC are overseen by ASPAC's Laboratory Proficiency Committee, comprised of a convenor and three others. A Technical Advisory Group operates between ASPAC and its proficiency service provider, who is now located in New Zealand.