ificial
manures used as supplementary to the farmyard manure, the frequency of
its application, and the nature of the soil.

These considerations naturally vary so much, that the quantities of
farmyard manure it is advisable to apply in different cases are widely
different. There is a strong probability that the rate at which farmyard
manure has been applied in the past has been grossly in excess of what
could be profitably employed. Opinion is gaining ground among practical
farmers, that smaller and more frequent applications of farmyard manure
to the soil would be fraught with better results than the older custom
of applying a large dressing at a time. This is an opinion in the
support of which science can urge strong arguments. It is only of late
years that we have come to recognise sufficiently the various risks
which all fertilisers are subject to in the soil, and the importance,
therefore, of minimising these risks as much as possible by putting into
the soil at one time only as much manure as it is safely able to retain.

"The famous old German writer Thaer regarded 17 or 18 tons as an
abundant dressing; 14 tons he called good, and 8 or 9 tons light. Other
German authorities speak of 7 to 10 tons as light, 12 to 18 tons as
usual, 20 or more tons as heavy, and 30 tons as a very heavy
application."[178]

In the new edition of Stephens' 'Book of the Farm,'[179] from 8 to 12
tons per acre for roots, and from 15 to 20 tons for potatoes, along with
artificials, which may cost from 25s. to 60s. per acre additional, are
quoted as general dressings.

The majority of recent experiments with farmyard manure would seem to
indicate that, even in the case of what are considered small dressings,
the extra return in crop the first year after application is not such as
to cover the expense of the manure. Of course, as is commonly pointed
out, the effect of farmyard manure is of a lasting nature, and is
probably felt throughout the whole rotation, or even longer. This, to a
certain extent, is no doubt true; still it may be strongly doubted
whether farmyard manure is, after all, an economical manure, as compared
with artificial manures. The desirability of manuring the soil and not
the crop is, in this age of keen competition, no longer believed in; and
the Rothamsted experiments have shown that it is highly doubtful whether
even the soil benefits to anything like a commensurate extent by the
application of large quantities of