Australian Soil and Plant Analysis Council soil and plant quality assurance programs and the impact of variability of test results on clients

Abstract

Summary. In relatively few years, the Australian Soil and Plant Analysis Council Inc. (ASPAC) has conducted 2 inter-laboratory proficiency programs on plant material and 3 inter-laboratory proficiency programs on soils. The purpose of these performance-based programs is to enhance the quality of soil and plant analysis in Australasia, with guidance where necessary from the soil and plant expertise of ASPAC members. ASPAC’s inaugural ‘Accreditation Committee’ reviewed published standards and existing laboratory accreditation/proficiency programs in Australia and internationally before developing what is now in full operation. This historical perspective and the 12 principles that guide operations of ASPAC’s soil and plant proficiency programs are described, as are the numeric procedures used to determine satisfactory performance. Certificates are issued to successful laboratories on completion of each program. Moreover, these remain current until signed certificates from the next equivalent program are released. Wide variations in some data sets suggest there is considerable scope to improve laboratory accuracy, particularly for soil chemical tests. Some of these differences are sufficient to markedly affect the assessment of fertiliser requirements. The present ‘Accreditation Committee’, in addition to State Representatives, serve as ‘points-of-contact’ for laboratories that require assistance to overcome problems with analytical accuracy and precision. ASPAC encourages its member laboratories to seek and maintain NATA (National Association of Testing Authorities, Australia) accreditation, in addition to participating regularly in the performance-based proficiency programs run by ASPAC.