of deep roots,
by inducing the growing plant to send down its roots into the lower
layers of the soil after the nitrate of soda. The benefit of deep roots
is, of course, very great. They enable the plant to withstand the action
of drought, and at the same time increase the area whence the plant may
derive its nourishment. Although the value of the manure is practically
entirely due to the nitrogen it contains, it has been urged that the
soda exercises a beneficial effect on the mechanical properties of the
soil, by increasing its power of absorbing moisture, and in also
rendering it more compact. This would partly explain how its results in
dry seasons are so much better than those obtained from sulphate of
ammonia. This mechanical action of nitrate can scarcely be very great
when we remember the comparatively small quantity applied. Even in the
driest of seasons there will always be sufficient moisture to secure the
diffusion of the nitrate of soda, while the risk of loss by drainage
will be reduced to a minimum. Much ignorance, as well as prejudice, has
existed in the past as to the true nature of the action of nitrate of
soda. Nor is this prejudice even yet entirely dispelled.

_Is Nitrate an exhausting Manure?_

The common charge brought against it is, that it is what has been termed
an exhausting manure. This objection, to have any weight, must mean that
nitrate of soda produces a crop which takes out of the soil an
_abnormal_ quantity of fertilising matter. But, so far as the writer is
aware, no scientific evidence has ever been brought forward to support
this contention. That the indiscriminate use of a manure may produce a
crop in which the stem and leaves are unduly developed at the expense of
the grain, or in which the quality of the crop may suffer from too rapid
growth, is, of course, a well-known fact. But as this could also be
produced by an overdose of soluble phosphoric acid as well as ammonia
salts, it is not a property that belongs exclusively to nitrate of soda.
Probably nitrate of soda has in the past been often used in this
indiscriminate way so as to produce such results. The fault, therefore,
lies not in the manure, but in the mode of its application. A few
remarks, therefore, on this most important subject may prove
serviceable.

_Crops for which it is suited._

Opinions will naturally differ as to the crops to which it is profitable
to apply nitrate of soda. Its value as a manure for ce