Proficiency testing scheme demonstrates consistency among soil analysts
Laboratories participating in the Professional Agricultural Analysis Group (PAAG) have completed the first full year of an independently administered Proficiency Testing (PT) Scheme which shows maintenance of consistent, high quality soil analysis results between the laboratories.
The PT Scheme, or ring test, was created to help ensure consistency of laboratory practice for soil analysis by independent assessment, helping maintain standards across participating laboratories. The scheme is operated by WEPAL of Wageningen University, Netherlands which operates soil proficiency tests in 294 laboratories in 60 countries.
A special UK scheme was established within WEPAL for PAAG to cover the main analytical methods for soil P, K, Mg and pH. Every quarter, WEPAL send samples of four soils to each of the 14 PAAG laboratories. Results are reported directly to WEPAL so that statistical comparisons among laboratories can be made.
"With no cause for concern regarding significant differences between laboratories in the first full year, the WEPAL scheme is showing that PAAG laboratories are operating to reliable, good standards," says Ian Richards, Consultant to PAAG. "Participation in the current testing scheme bodes well for maintaining this position in future."
PAAG also provides a forum for member laboratories to discuss proficiency testing results, analytical procedures and issues at regular technical meetings involving both commercial and research laboratories.
As Jane Salter, Chairman of PAAG explained: "Soil analysis is a recognised basis for fertiliser recommendations so it is vital that laboratory analysis is carried out consistently and to high standards. Members of PAAG are committed to this.
"Of course, laboratories’ analysis can only provide information based on the samples provided. Therefore, there is a shared responsibility with farmers and FACTS Qualified Advisers to collect representative samples from the field. Only by operating to the highest standards in every procedure from field to laboratory can a dependable soil analysis report be produced to underpin decisions on nutrient management and fertiliser application."
