use of 'Concentration' and 'ConcentrationRatio' for S06 chemistry

[meganrwong]

Feedback welcome, logging issue and decision reached

Have decided not to use 'proportion' for S06 of for any of the soil chemical parameters measured by procedures in the 'green books'.

Did not use Mass Ratio either. ConcentrationRatio was used. Total organic carbon (TOC) to total soil nitrogen (TSN) could be Mass Ratio - but have used concentration of in all of the underlying methods, because they inconsistently say 'report as concentration', though all report in %.

And, it is not clear in S06 examples what when 'proportion of ' v 'concentration of' should be used. So, for now, have just used 'concentration of' in all instances

Though 'proportion' may make more sense in some cases (community feedback welcome), the rationale for using 'proportion' consistently for the soil chem parameters could not be determined

Concentration was used for everything reported in percentages, MassRatios eg in mg/kg , MassConcentrations eg in ug/L and AmountOfSubstancePerUnitVolume eg cmol/L

see terms used in BODC S06 - https://vocab.nerc.ac.uk/collection/S06/current/

[meganrwong]

related to #nvs-vocabs/P01/issues/208