Spirit of the age. [volume] (Raleigh, N.C.) 1849-1865, 1854-12-20

The ashes of plants are called inorganic
matter. Though apparently homogeneous,
these ashes have certain distinctive features
which are important to the farmer The
same plant, without reference to the soil on
which it grows, always Yields an ash of about
the same composition. Different classes of
plants yield different kinds of ashes. Inor-
ganic or ashy matter is obtained by plants
only from the soil. 1t is of mineral char
acter, and never exists naturally in the 80 /
mosphere From these facts we see that the |
soil, in order to produce perfect plants, must
contain the matters necessary to form their
ashes, while these being different in the va
rious crops, the soil may be fertile for one
crop and not for an other, because the pro-
portions Of its Inorganic materials may be
such that it can furnish food for the ashes of
but one kind Of plant. Other soils are again
fertile for all plants, and if we examine these
by chemical analysis, we shall find that they
contain all that is necessary for forming the
ashes Of all plants.
The first fact that strikes us in studying
the composition of vegetable ashes is that
they consist Of the same substance in all
relative proportions to each other. These
substances are called pota>h, soda, lime, mag
nesia, phosphoric acid, sulphurc acid, chic
rine, "a constituent Of common salt, y silica,
(the base of sand) oxide of iron, Tor iron
rust and in some plants oxide of magnesia.
These constituents, except the last named,
exist in all of our cultivated plants, the pro-
portions varying with the kind of plant
For instance, the ashes of wheat and other
seeds contain large proportions of phospho-
ric acid, the potatoe yields much potash, clover
possesses large quantities of lime, etc. The
relations between the soil and its natural
) productions seem to be invariable, and we
observe in practice that, other things being
equal, q soil in which phosphoric acid large
5 ly predominates is best for wheat. rye, corn,
: &c. An excess of potash iss the soil for po-
t tatoes. Lime induces growth of clover or
e other plants having ashes for similar compo-
e sition.
), The same principle explains another ap-
r parent peculiarly Of cultivation. It is often
r observed that soils which are fertile for one
b crop refuse to produce it after few years
cultivation, though they will produce some
y other crops in abundance. The reason fol
st this is that the constant production ola sin
'e gle kind Of plant robs the soil chiefly of one
| or two ingredients, until they are too much
h reduced in proportion to afford proper sus
'e tenance to plants requiring them SO largely
y though it may still contain other Ingredient
3 in sufficient quantity to sustain another elias
N ofplants. Thus successive crops Of whea
? rob the soil of its phosphoric acid, while the
y require its potash in less quantities. Sup
10 posing the two constituents to have existe
De in equal proportions at first, at the end c
Id five years of wheat growing there would b
at remaining in the soil more of potash than {
phosphoric acid, and it would be better ftte
ip for the growth of potatoes than for that whea
1t On this principle is founded the rotation
he crops, which consists Of eultivatingsay thre
I'D or FIVE kinds of crops in yearly succession
an thus SO varying the demands on the soil ths
lss it supplies the various kinds of morgan
on matter in about the same proportions, an
nd is left at the end of the rotation in prop
u.s. baLance-that is, having no constituent larg
ith ly predominating over the others. Viii
ce, or this subject, we may mention avery plau:
n, ble theory on the subject of weeds. 1t
ess the natural tendency ofsoils to produce spo
Ter taneous growths of plants, the compositir
of of whose ashes correspond with their own.-
it Many ofthe more noxious weeds differ great
an, in their inorganic parts from crops which
90 wish to cultivate, and when the ash of {
ris- weed corresponds more closely with the $
es.' than it does that Of our crop, the weed /