Jury-Law books

It cannot be believed that the water-washed soils of the East
retain as much fertility as the dry soils of the West. Hilgard has
made a long and elaborate study of this somewhat difficult question
and has constructed a table showing the composition of typical soils
of representative states in the arid and humid regions. The
following table shows a few of the average results obtained by
him:--

Partial Percentage Composition
Source of soil Humid Arid
Number of samples analyzed 696 573
Insoluble residue 84.17 69.16
Soluble silica 4.04 6.71
Alumina 3.66 7.61
Lime 0.13 1.43
Potash 0.21 0.67
Phos. Acid 0.12 0.16
Humus 1.22 1.13

Soil chemists have generally attempted to arrive at a determination
of the fertility of soil by treating a carefully selected and
prepared sample with a certain amount of acid of definite strength.
The portion which dissolves under the influence of acids has been
looked upon as a rough measure of the possible fertility of the
soil.


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