Year: 1871

If crops Of any kind are raised fire.
quently off ground without restoring
anything back by manuring, it is found
that the produce gradually diminishcs,
because the ingredients necessary to
sustain the growth Of the crops have
been exhausted. 1t has been long
known that this cxhausting power, al.
though exercised by all crops, yet
varies very much in individual ones
It may be safely said that every plant
diminishss the fertility of the spot on
which it is grown, especially when no
part Of it is returned to soil.


The whole art of manuring consists
in returning compens tion for the in
gradients which have been extracted by
the crops and sustaining the fertility Of
the soil. 1t is better to prevent the ex-
haustion of the soil than to cure it, and
the best method of doing so is by the
introduction of judicious rotation, or
alienation of unlike crops. In adopt
ing such rotation we only copy from
nature. in the natural forest many
generations of broad -leaved trees live
and die and succeed each other; but
the. time comes at last when a general
pestilonce seems to assail them all; their
tops droop and wither, their branches
fall off, and their trunks rot; they die
out and narrow-leaved race succeeds
them.


This race again runs its course Of
centurie perhaps; but death scizes it
too, and the broad-leaved trees again
make their appearance. In like man
ner the old meadow and pasture change,
different varieties Of grasses succeeding
each other as the fields increase in age
The alienation Of crops therefore as
serts to its IF s,nlcthinS Of the dignity
of natural law, and man is right when
he initiates nature. But upon what do
the good effects of rotation defend?
Why do the broad-leavcd trees alter
nate with the narrow in the ancient for
est? Why do the grasses change in
the old meadows? Why does the far
mer obtain a larger produce, and for a
CRATER number of years, by growing un-
like crops alternately, than by continu-
ing, year after year, to grow the same?


The reason is not merely that one
crop carries off more, and another crop
less, Of those ingredients whicn crops
derive from the soil, but that one crop
carries off more of one thing, another
crop more of another. Grain carries
off phosphorous, the straw silica, the
bulb alkaline matter. After several
crops of the same kind, the surface soil
through which the roots have spread
becomes so poor in these substances
which the crop specially requires, that
the plant cannot obtain from it suffi-
cicnt supply to n"urish and bring it to
maturity. In the case of cereal, the
fast effect scarcity, say of phosptoric
acid, ls to make the ear smaller and the
number OF grains less ; the ncxtt to con,
tinue the growth until very late in the
autumn without ripening.


But suppose we alternate wheat
crop, which in its grain carries of
phosphoric acid, with a hay crop which
requires much silica, or root crop tn
which much alkaline matter is neces.
sary-then the one would live upon
and remove what tie other had left in
the greatest abundance. Instead ol
robbing the soil every year Of the same
substances we should be cxhausting it
more equally of all, and we should be
able, for double the time at least, to
crop it without the risk of entirely ceas-
ing to give us profitable return. The
greater the variety of the crops we grow,
and the longer the interval between the
successive crops of the same kind, the
more perfectly do We avail ourselves Of
the benefits of rotation. No rotation
it is true, however skilful, will alone
prevent the land from becoming ulti-
mately exhausted Nothing but regu-
lar and generous manuring will do this;
but rotation affords the very best op-
portunity Of applying manure to every
field at regular intervals of time, and
also of destroying weeds which always