Amorphous Mineral Colloids — Kanehiro and Whittig 
481 
The fact that amorphous colloids greatly affect 
properties of soils where they are dominant con- 
stituents emphasizes the need for more critical 
examination of our soils for evidence of their 
presence. According to Kanehiro and Sherman 
(1956), it is well established that aliophane 
has low bulk density, high water-holding capac- 
ity, and, in some cases at least, a high cation ex- 
change capacity. In addition it has been observed 
that aliophane has a strong aggregation effect 
on soils, a very high phosphate fixing capacity, 
and the ability in some cases to fix organic com- 
pounds so as to render nitrogen available with 
difficulty to microorganisms and higher plants 
(T. Sudo, private communication ) . 
Early researches of Burgess and McGeorge 
(1926) and Burgess (1929) in Arizona sug- 
gested that amorphous alumina, silica, or alumi- 
nosilicate may be formed quite readily in soils 
by application of alkaline solutions. Kerr (1928) 
further postulated that amorphous aluminosili- 
cates may form even in slightly acid soils as a 
result of local hydrolysis of feldspars, solution of 
alkaline silicates and aluminates, and subse- 
quent co-precipitation. 
The Pacific region and its adjacent areas, 
with their recent volcanic materials offer a 
splendid opportunity for investigation of the 
presence of, the properties imparted by, and 
the mechanisms of formation of, such amor- 
phous constituents in soils. 
SUMMARY 
The work on the amorphous mineral colloids 
of soils of the Pacific region and its nearby areas 
is described. 
The amorphous colloids, especially aliophane, 
dominate the clay fraction of many soils de- 
rived from volcanic ash, as well as some rocks, 
in the Pacific area. Soils dominated by these 
amorphous colloids have many distinct and 
unique properties. The position of the amor- 
phous colloids, especially of aliophane, in the 
weathering sequence remains to be fully clari- 
fied. 
For many reasons, the identification of amor- 
phous colloids is often difficult; however, re- 
cent improvements in instrumental techniques 
have greatly facilitated this identification. 
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