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The chemical composition of the
frozen peat differs greatly from
that of the unfrozen peat in the same profile .
This difference is
shown in profiles T28A,
T35A and T27C, where the pH was found to be
approximately 2, the exchangeable calcium 4 to 8 m .e ./100 gms and
the exchangeable hydrogen 70 to 85 m .e ./100 gms in the unfrozen active
layer . By contrast, the pH of the frozen peat layer was between
pH 3 .0 and 4 .7, the exchangeable calcium approximately 30 to 69
m .e ./100 gms and the exchangeable hydrogen 43 to 85 m .e ./100 gms . The
large amount of calcium in the frozen layer results from water migration
along the thermal gradient as well as other factors, as has been
explained by Tarnocai (1972) . It is also interesting to note that
the calcium concentration of ice from the ice wedge (water sample 114)
is lower than that from the water sample (111) taken from a waterfilled
unfrozen polygonal trench .
This indicates that nutrients like
calcium are freed from the ice during the process of ice formation
and occupy the exchangeable sites on the organic soils,
thus resulting
in a higher nutrient concentration and pH in the frozen soil .
The pH of the sample (114) obtained from an ice wedge,
however,
is higher than that of the open water (sample 111) in spite of the fact
that a large amount of calcium has been removed from the system,
indicating that other chemical changes are also taking place due to
ice formation .
9 .2 . Mineral Soils
The
unfrozen mineral soils developed under forest vegetation
generally have the properties of
forest soils found elsewhere in the