Soil Sequences in the Hawaiian Islands 1 
G. Donald Sherman and Haruyoshi Ikawa 
The wide range of conditions under which 
soils have developed in the Hawaiian Islands 
has produced a pattern of soil geography which 
reflects the differential influence of the intensity 
and capacity factors of soil weathering. 
Soil formation is the product of two actions, 
weathering (W) and leaching (L), on the sur- 
face and near the surface of the earth’s crust. 
Weathering is the process of mineral decomposi- 
tion, and leaching is the solution of more or less 
soluble constituents and their removal in the 
percolating waters. Both of the processes occur 
at different degrees of intensity but under the 
normal temperatures and pressures of the 
earth’s surface. Soil is formed from its geolog- 
ical parent materials by decomposition of vari- 
ous products of volcanic action in situ or after 
their transportation either in their natural state 
or after the action of various agencies of disin- 
tegration and erosion, or after partial or com- 
plete decomposition to secondary minerals in 
situ or after deposition of more or less soluble 
constituents. In all instances soil is the product 
of these actions on the surface under the pre- 
vailing environment to form surface horizons 
which are distinct and parallel to the topo- 
graphic surface rather than to the geological 
formations of the earth’s surface. 
The weathering action in soil formation 
(WxL) is strongly influenced by intensity fac- 
tors of environment and time, and by capacity 
or inherent (resistance) factors of the parent 
material. The intensity factors are age or time 
of exposure (A), climate, including tempera- 
tures and rainfall (C), drainage (D), and 
vegetation (V), all of which govern the rate of 
action. The capacity factors are size of the units 
or texture (T), the inherent stability of mineral 
to decomposition (M), and the nature of the 
surface of mineral unit or coating (S). Thus 
1 Published with the approval of the Director of 
Hawaii Agricultural Experiment Station as Technical 
Paper No. 911. Manuscript received September 22, 
1967. 
the rate of soil formation may be expressed by 
the formula: 
K (rate of soil formation) = (WxL) 
ACDV 
TMS 
Since this reaction theoretically has been in 
existence since the formation of the earth’s 
surface, K is a dynamic transitory equilibrium 
which is proceeding toward a system having 
some form of static equilibrium. In reality it can- 
not become a static system, since, over geological 
time, almost imperceptible changes continue to 
occur causing real changes. Therefore the sys- 
tem is considered a dynamic static system. Thus 
the products of soil formation will occur as a 
sequence, reflecting the influence of age, climate, 
etc. The members of a sequence in the early 
dynamic stage will exhibit great variation, but 
with time (A) it approaches a dynamic static 
system as the influence of the intensity and capa- 
city factors approach zero. During this process, 
then, soils in any environmental area range from 
great variability in early stages to a high degree 
of uniformity in old age. 
Sequences of soils in Hawaii occur which re- 
flect the differing degrees of dominance of one 
or more of the soil-forming factors during the 
process of soil formation from a single type of 
parent material — e.g., in the different areas of 
one lava flow. Studies are being made of the 
inter-relationships of the soils in these sequences 
as means of gaining a better understanding of 
soil genesis. The soils of these sequences reflect 
the effect of increasing intensity of the soil- 
forming factors, as, for example, increasing 
amounts of annual rainfall, age or increasing 
time of exposure to weathering processes, and 
increase in the amount of specific surface in the 
weathering material due to differing rock tex- 
tures. 
The Hawaiian Islands are a natural labora- 
tory for the study of soil formation. The islands 
have a remarkably uniform subtropical climate 
with very little difference between the mean tem- 
peratures of winter and summer. On the other 
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