Description_x000D_ General description_x000D_ This proficiency testing sample is produced in accordance with ISO/IEC 17043:2010. All information regarding the use of this material can be found in the reporting packet supplied for each sample._x000D_ Other Notes_x000D_ Proficiency testing samples are presented as single blind. No values for the samples are released until the testing period concludes. Values of analytes vary lot to lot._x000D_ Proficiency Testing Schedule (2020-2021)_x000D_ Soils_x000D_ LPTP20-S1 January 29 - March 13, 2020_x000D_ LPTP20-S2 April 8 - May 22, 2020_x000D_ LPTP20-S3 July 22 - September 4, 2020_x000D_ LPTP20-S4 October 7 - November 20, 2020_x000D_ LPTP21-S1 January 27 - March 12, 2021_x000D_ LPTP21-S2 April 7 - May 21, 2021_x000D_ LPTP21-S3 July 21 - September 3, 2021_x000D_ LPTP21-S4 October 6 - November 19, 2021_x000D_ Quick-Turn Study - (non-scheduled proficiency test that is available at any time)