the crop requires
should be of the slowly rotting or dissolving kind, as uniformly
distributed through the soil as possible."

_Experiments by the Author._

Experiments by the author on turnip-manuring, carried out in different
parts of the South and West of Scotland, showed that while farmyard
manure is valuable in giving the crop a good start and bringing it well
forward during the period of germination and early growth, by supplying
a certain amount of easily assimilable plant-food, and in the case of
dry weather attracting a quantity of moisture, its application in
quantities of 20 or even 10 tons per acre can scarcely be regarded as
profitable, giving to farmyard manure a nominal value of a few shillings
a ton. In these experiments slag proved itself a most valuable manure,
indeed one of the most economical of all the manures experimented with.
They further showed that heavy dressings with superphosphate, amounting
to as much as 8 cwt. per acre, are, from an economical point of view, as
a rule justifiable in Scotland; and that nitrate of soda and sulphate of
ammonia possess practically equal value as a manure for turnips. In
almost every one of the experiments the benefit of supplementing
superphosphate with nitrogenous manure was shown. Potash was also found
in many cases to be a thoroughly paying manure for the turnip crop, when
it was applied along with nitrogen and phosphates; but when applied
alone, far from exercising any appreciable benefit, it seemed to exert
an injurious action.

POTATOES.

Potatoes are often classed along with the root crops, and in their
manurial requirements they offer many points of similarity. Next to root
crops, they may be said to make the most exhaustive demands on the soil,
and therefore require a liberal general manuring. A point of importance
in the manuring of potatoes is a good tilth in the soil, so as to enable
a free expansion of the tubers to take place. They may be said to grow
best on deep warm soils; but, like roots, if liberally manured, they may
be successfully grown on any kind of soil. Farmyard manure has long been
regarded as specially valuable for the potato crop. In many parts of
Scotland it is applied in enormous quantities, ranging from 20 to even
40 tons per acre. There can be little doubt that the value of farmyard
manure, as well as other bulky manures, for the potato crop, is partly
due to their mechanical influence on the soil. Potatoes are
surface