sixty-one small islets ranging in size from a fraction of an
acre to the largest, Rongelap, which is four miles long and
one-half mile across at its widest point.
There is one small
islet on the western reef and the other islets extend along the
northern,
eastern and southern reefs.
The
islets on the
northern reef are not as well developed as those to the east
and south.
There are two seasons--a dry season from December
to March and a wet season from April to November.
Annual rain-
fall is less than fifty inches, and there is no well-developed
fresh-water lens.
Some important features of Rongelap Atoll
including aerial photographs are given by Wiens
(1962).
Classification and mapping of the soil types at Rongelap
Atoll were reported by Kenady (1962).
primarily calcium carbonate,
The parent material is
originating from corals,
minifera, coralline algae and mollusk shells.
small amount of pumice drift in the soils.
fora-
There is a very
Since these soils
contain no inorganic colloids,
exchange capacity and organic
content are linearly related.
In some areas,
particularly
along the seaward sides of the islets, buried AL horizons are
found as deep as eighty inches (Fig. 1).
These highly
.scganic
horizons presumably result from storm debris covering previously
established soil and vegetation.
The pH, determined in the field from a 1:1 soil-water ratio
with a Beckman
Model
N-2
pH meter, is generally between
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