Vermont watchman and State journal. [volume] (Montpelier, Vt.) 1836-1883, 1883-03-07
As regards the various conditions in which
phosphoric acid is found in these fertilizers,
the following explanations are made by the
Connecticut chemists

As regards the various conditions in which
phosphoric acid is found in these fertilizers,
the following explanations are made by the
Connecticut chemists
Soluble Phosphoric acid implies phosphoric acid or
phosphates that are freely soluble in water. 1t Is
the characteristic ingredient OF superphosphates,
in which 1t is produced by acting on "insoluble J"
or reverted" phosphates with oil Of vitriol. 1t
is not only readily taken up by plants, but Is dis
tributed through the soil by rains. Once well in
corporated with soil 1t shortly becomes reverted
phosphoric acid.
Reverted (reduced or precipitdted) Phophoric
acid sti ctly means phosphoric acid that was once
freely soluble in wafer but from chemical change
has become insoluble in that liquid. 1t Is freely
| taken up by strong solution Of ammonium cit
rate which is therefore used in analysis to deter
| mine Its quantity. Reverted phosphoric acid I"
| implies phosphates that are readily assimilated by
crops but generally have less value than soluble
| phosphoric acid, because they do not distribute
| freely by rain.
| InsolubIe Phosphoric acid implies various phos-
pilates not freely soluble in water ammonium
citrate. In some cases the phosphoric acid Is too
iDsoluble to be rapidly available as plant food.
This IL true Of South Carolina rock phosphate, Of
| Navassa phosphate, and especially of Canada
apatite. The phosphate OF coarse raw bones Is at
first nearly nsouble in this sense because Of the
animal matter OF the bone which envelopes 1t, but
when the latter decays in the soil the phosphate
| AS''i'ho "a eSoth'iohJ sho iO'Oiteo ioAh
These matters are worthy of careful study
| by those farmers who make use Of CONNER
cial fertilizers. While the prices given
may answer the purpose of the chemist, and
may indeed be the nearest expression of
their actual commercial value to which he
can attain, it should be understood that
this commercial value may be easily changed
by change in the willingness of consumers
to buy fertilizers in such or such forms.
If farmers purchase indiscriminstely, and
without proper knowledge, the prices will
depend upon the course of the wholesale
market for the raw material and the con-
venience or interest of manufacturers. II
farmers, however, are "posted," and gener-
ally refuse, for instance, to buy "soluble u
cents pound in superphosphate when
they can buy "reverted superphosphste in
medium ground bone at five cents pound
or insoluble superphosphate in fae
ground Charleston rock phosphate at three
and one-half cents pound, the price Of the
"soluble article will come down " what
the farmers are willing to give for it. As a
matter of fact the high priced soluble pbos
phate becomes reverted in the soil in few
hours, and the only possible superiority it
has consists in the fact that for the few
hours it remains soluble it. is being more
evenly distributed in the soil. All fertile
soils contain phosphate of lime in the /" in
soluble form, aud yet plants growing in
them get enough for the most luxuriani
growth, thus showing that though this min
eral may be insoluble" in pure water in
a chemists laboratory, it is sufficiently sol
uble in the water Of the soil 10 enable
plants to get all that they need in the goot
soil. 1t is also a fact that the phosphorit
acid of stable manure is not in the form
which the chemist calls soluble" yet it il
available to crops. 1t is because this tbinl
is not sufficiently understood that farmer
persist in buying the "soluble phospbat,
OF commercial fertilizers at twelve and one
half TO eighteen cents pound when the,
can get the same thing in ground bone q
five cents. We say from twelve and one
half to eighteen cents, because nearly al
tha commercial fertilizers sold in New
England, when analysed and their valu
calculated according to the table givel
above still fall short of the selling pric
from 30 TO Sl5 on ton. Aud yet at tn
estimated chemical value the purchaser i
giving twelve and onehalf cents poun,
for soluble phosphoric acid, and twent
to twenty four cents pound for nitrogen
when he can get his phosphoric acid III
the same form that it exists in the bes
stable manure, hog manure, sheep manure
hen manure, or Peruvian guano) for fiv
cents pound in ground bone, and his nj
trogen for from twelve TO fifteen cents pc
pound in the same. We think (and W
speak from long continued practics
experience) that this is preposterous differ
ence, entirely upjustifed by the agriculturs
value of these substances az seen in tn
growth of crops. But as long as farmer
can be hoodwinked into buying fertilizer
at $40 and $50 ton that anallze only 50
to Si2, and are brought up to even thi
. price by allowing such an extravagant rat
for soluble phosphoric acid and ammonil
they will be so sold. Knowledge is wort
money ia this mstter,-as much 30 as 1
any with which farmers have to deal. Tn