The Florida agriculturist. [volume] (DeLand, Fla.) 1878-1911, 1881-03-23
What Constitutes Plant Food.
E,.ou, he Methodist Advocate.

and what constitutes genuine plant
fond. have been dealing IN ana
usino fertilizers for lorg time, ana
when people ask me. is your guano
good for cotton, or good for wheat
and tobacco?.I don't know what to
saw more than to say, yes; and tell
them, if they will show me Ter
tilizer that will bring good tobacco,
l will show them one that VIII DIlng
cotton. wheat, corn, or anything elsei
that pIant food is plant food in the
same sense that corn is animal food;
and as corn will tatten all the various
animals that feed upon 1t, SO VIII
good plant food tatten and grow the
whole vegetable kingdom that feeos
upon it. suppose there is no one
element wanting in good stable ma
nure to meet every condition OF nrst
class plant food, and everything that
it is applied to grows and tattens py
consuming it, provided there is the
presence OF sufficient moisture. Ii
this be true of stable manure, why
not also true of first class manlpu-
lated or natural guano ?-FETER
PURYEAR, Boydton, Va.
Our correspondent is about right.
All plants take up, though IN diner
ent proportions, the same substance
from the soil. Plants feed both from
the atmosphere and the soil. AS TO
three of the organic elements OF
plants, carbon, oxygen and hydrogen
we give ourselves no trouble, as tney
are furnished by the atmosphere Id
the form of carbonic acid gas and
water. The remaining organic ele-
ment, nitrogen, is matter CT the
highest concern. The sources ofsup-
ply are comparatively scanty ana
nrecarious. Plants obtain their nit
rogen from the nitrates or ammonia
and its salts. The value of Peruvian
guano depends chiefly on the amount
of ammonia it contains. No plant
can grow without an available source
of nitrogen; and to grow luxurlantly,
it must have an abundant source OF
available nitrogen. All concentrated
fertilizers that contain in sufficient
quantity and in available form the
nitrates or ammonacal compounds,
meet this universal demand OF grow.
ing yegeraJion.
Though these four elements-car-
bon, oxygen. hydrogen and nitrogen
are derived principally from the at
mosphere, yet plants, as they grow in
our soils, composed of organic and
mineral matter, obtain them partly
from the atmosphere and partly from
the soil.
The ash of plants comes exclusive.
" from the soil. This ash is made up
ri nine substances, and all are neces-
sary to plants. In regard to some of
them. also, we have no trouble, be
cause they exist abundantly in pretty
we'll all soils, and plants take them
| mn in small proportions. The case
would be altogether exceptional and
unusual Of a plant suffering, for IN
J stance. from lack of silica aud oxide
iron, for the double reason, that these
substances exist abundantly in nearly
ali soils, and plants take them up III
smal.quan,ities. Butt plants constantly
suffer from lack Of potash and phos
nhoric acid, because the demands OF
growing vegetation for these sub
Stances are heavy, and The soil con"
tains them i'll quantities relatively
small. Let us illustrate: OF the nine
a,hOtances that constitute the ash oil
the grains of wheat, the phosphorIc
acid weighs as much as the other
eioht substances together. But the
amount of phosphoric acid, even in
rich soil, is only 4 1Oths of ! pei
cent or A. 1Oths OF pound OF phos
nhoric acid, in 100 pounds OF soil. II
= very seldom that soil contains
even this much OF phosphoric acid.
Again: Two thirds OF the ash o.
tobacco is made up OF potash and
lime but potash and lime together
make up 6 per cent. or less OF the
weight of fertile soil.
Cotton demands chiefly, and in the
ordar mentioned, lime, potash and
nhosnhoric acid. A fertilizer that Is
rrood Tor tobacco, or the cereals (oi
Which wheat is the type), is good tol
cotton, and it is particularly good fol
ootton if it has been found good 1ol
both tobacco and the cereals, as cot
ton combines the demands both o.
the cereals and tobacco.
Now in manufacturing fertilizer
The leading consideration should be
10 supply these constituents OF plant
tood which growing vegetation most
largely demands, and which are best
asJ - he supplied ia sufficient