How to take action in case of low performance in PT. Yuji Maejima and Takashi Kanda, Soil Inventory Unit, National Institute for Agro-Environmental Sciences, NARO

1. Soil Inventory Unit
National Institute for Agro-Environmental Sciences,
NARO (Japan)
Dr. Yuji MAEJIMA and Dr. Takashi KANDA

2. Results of 2018 and 2019 Proficiency Testings
Can you please tell us about the results of
your lab in the frame of the 2018 SEALNET PT
and 2019 GLOSOLAN PT?
2018 SEALNET PT Z-score
pH (ratio 1:2.5) <2
OC dry combustion <2
P-Olsen <2
Exch. K in NH4OAc <2
2019 GLOSOLAN PT Z-score
pH (ratio 1:2.5) <2
OC dry combustion <2
P in Olsen <2
P in Bray I <2
P in Bray II <2
Exch. K 2<|Z|≤3
Exch. Ca <2
Exch. Mg <2
Exch. Na 2<|Z|≤3
EC by 1:5 |Z|>3
Ranges Evaluation results
|Z|≤ 2 Satisfactory
2<|Z|≤3 Questionable
|Z|>3 Unsatisfactory

3. Actions taken
Can you please tell us what actions your lab
has taken in order to improve its analytical
quality after the 2018 and 2019 PT results?
No action except with EC was taken in our lab.
Our action for EC results
We checked again our experimental results, and found that our
reported values of EC was 100 times higher than the measured
value.
It was careless mistake because the previous reported units of
EC was not 'dS/m' but 'mS/m'.

4. Thanks for your attention