Meaning of "within"

Over the years I've encountered pedons described with diagnostic features / properties occurring "on the line" between different taxonomic groups.

The word "within" is used throughout ST. Most often in the context of some material of some thickness/diagnostic feature occurring within a certain depth. Many of these usages are unambiguous due to other requirements for particular taxa, but to my knowledge it is not defined whether the limit implied is inclusive or exclusive when root-limiting layers are involved. Does "within" mean "less than" or does it mean "less than or equal to"?

Two ambiguous examples...

1) Particle size control section: Shallow soils that have a root limiting layer WITHIN 36 cm have a PSCS from the mineral soil surface to the restriction (the whole thing). Therefore, a shallow soil with mineral soil surface at 0 cm and a lithic contact at 37 cm has a PSCS from 25 to 37cm.
For a shallow soil with mineral surface at 0cm to a lithic contact AT 36cm -- is the PSCS from 0 to 36cm or 25 to 36cm?

2) Lithic Dystroxerepts: Other Dystroxerepts that have a lithic contact WITHIN 50cm.
If the contact occurs AT 50cm, does the pedon key out Lithic?

Some places in ST are unambiguous with these types of limits. For example in the Key to Soil Depth Classes, "less than" is used in for shallow families where a root-limiting layer occurs but the soil is not in a Lithic subgroup.

It seems like the implication of this is that "within" means "less than" ... and not "less than or equal to" ... at least in the context of depth class. That might be a bit of a leap. However, if that is not what it means then the depth to restriction limits for shallow families and lithic subgroups have different requirements.

This case might be resolved with more explicit wording, for example:
"Lithic Dystroxerepts: Other Dystroxerepts that are less than 50cm from the mineral soil surface to a lithic contact."

Looking forward to hearing folks input on this!



Edited 4 time(s). Last edit at 06/02/2017 08:42PM by agbr0wn.