Organic matter (Humus) 3.5
Soluble inorganic matter 12.0
Insoluble silica and silicates 84.5
--------
100.00
The organic matter is available for plant growth.
The inorganic matter, soluble in dilute hydrochloric acid, is (with the
exception of the alumina it may contain) composed of fertilising
material. The substances found in the soluble inorganic matter of soils
are lime, magnesia, alumina, silica, phosphoric acid, oxide of iron,
oxide of manganese, potash and soda. The insoluble mineral matter is
nearly all silica. There is very little clayey matter in any of the
soils--not more than about five per cent. All the soils are remarkably
free from stones or pebbles, or even coarse sand.
From the above it will be seen that these soils, while possessing a
large amount of matter available for plant growth, are exceedingly
friable, and would be very easily worked. They would absorb heat
quickly, and from their porosity would require little drainage, and so
would be both warm and dry soils, and form fertile land suitable for
almost all kinds of agricultural and horticultural produce.