00 |
| |==========|===========|===========|
+-----------------------------+----------+-----------+-----------+

It is unnecessary to multiply analyses of fertile soils, those now given
being sufficient to show their general composition. They are all
characterised by the presence, in considerable quantity, of all the
essential constituents of plants, in a state in which they may be
readily absorbed. The absence of one or more of these substances
immediately diminishes or altogether destroys the fertility of the soil;
and the extent to which this occurs is illustrated by the following
analysis of a soil from Pumpherston, Mid-Lothian, forming a small patch
in the lower part of a field, and on which nothing would grow. Being
naturally wet, it had been drained and sowed with oats, which died out
about six weeks after sowing, and left a bare soil on which weeds did
not show the slightest disposition to grow.

SOLUBLE IN ACIDS.

Soluble silica 0.173
Peroxide of iron 6.775
Alumina 1.150
Oxide of manganese trace
Carbonate of lime 0.856
Magnesia 0.099
Potash 0.132
Soda 0.123
Phosphoric acid trace
Chlorine trace
---- 9.308
Silica 73.096
Peroxide of iron 1.371
Alumina 4.263
Lime 0.858
Magnesia 0.520
---- 80.108
Organic matter 8.012
Water 2.391
---- 10.403
------
99.819

In this instance the barrenness of the soil is distinctly traceable to
the deficiency of phosphoric acid, sulphuric acid, and chlorine. There
is also a remarkably large quantity of oxide of iron, which, when acted
on by the humic acid, is well known to be highly prejudicial to
vegetation, and that this took place was shown by the fact that the
drains, a couple of months after being laid, were almost stopped up by
humate of iron. Still more striking are the following analyses:--

+----------------------+-----------------+------------+-------------+
| | Moorland soil | Sandy soil | Soil from |
| | near Aurich, | near | near |
| | East Friesland. | Wettingen. | Muhlhause