Pergelic subgroups were eliminated from SOIL TAXONOMY when the Gelisol
order was established. It is well documented, however, that there is
substantial acreage of soils having a MAST of 0 C. or less without
permafrost or gelic properties within 2 meters. These are primarily
coarser grained alpine soils where diurnal temperature fluctuations result
in MAST less than 0 C., but the soil temperature is not perennially ) C.
or less.
Under the 8th Edition of the Keys, these soils fall into cryic suborders
or great groups and are not distinguished from soils having a MAST greater
than 0 C.
Alaska soil scientists are developing a proposal to recognize pergelic
subgroups where necessary (this includes Haplocryods, Dystrocryepts,
Eutrocryepts, and others). We would like to hear comments both pro and
con on this issue. Also, if you are in support and have data, we would
appreciate the assistance in developing the proposal.
