The Marietta journal. [volume] (Marietta, Ga.) 1866-1909, 1893-11-30
COMMERCIAL FERTILIZERS.
Their Percentages of Valuable Plant
Food.

WIN wi { NSIAL TEN IEIZEHS.
Their Percentages of Valuable Plant
Food.
, We are often asked by farmers why il
is that so much unnecessary material il
found in the ordinary fertilizers on the
market. A common composition Of
these goods is about 10 per cent of avail
able phosphoric acid, about 2 1-2 pei
cent ammonia and about per cent pot
ash. This is a total of IA 1-2 per cent OF
available plant food, or IA 1-2 pounds il
every 100 pounds of fertilizer.
This may appear small percentage
yet when the source of the materials
and the urgent demand for low priced
fertilizers is taken into consideration,
there are excellent reasons for such q
condition of affairs.
There are certain materials offered
upon the market which contain plant
food, some of them are sold at very low
prices which make them available as
fertilizers. Bones. phosphate rock, cot
tonseed meal, blood, tankage, sulphate
of ammonia, nitrate of soda, muriate of
potash, sulphate of potash and kainit
are such materials.
Phosphate rock is our cheapest and
most used source of phosphoric acid;
cottonseed meal is one of our cheau
sources of nitrogen, and kainit is largely
used as source of potash.
Now 100 pounds of phosphate rock
only contains about 80 pounds of phos
phoric acid, and to render this 30 pounds
of phosphoric acid available as plant
food requires in round numbers about
100 pounds of sulphuric acid added to it
Then the 200-pound mixture will con.
tain the whole of the 30 pounds of the
phosphoric acid, or 10 pounds in 100; or,
III other words, it will be Is per cent
''acid phosphate" Phosphate rock is a
combination of lime with phosphoric
acid, and it also contains some inpuri-
ties such as sand, etc. Sulphuric acid
when added to phosphate rock seizes a
large portion Of the. lime and forms sui.
phate of lime, leaving the phosphoric
acid available as plant food. If it were
possible to secure perfectly pure phos-
plate rock we could only make about O
% per cent "acid phosphate with it by
this process. 1t is possible to leach out
the phosphoric acid from the "acid phos.
phate" and evaporate the solution down
and thus produce a remarkably high
grade of "acid phosphate" This. OF
course, increases the cost of the goods
very much. 1t is possible now to buy
goods running from 40 to so per cent
available phosphoric acid, but the de-
mand is limited, as everyone wishes
cheap fertilizers. Such an article is j
trinsically worth three times as much as
Is per cent acid phosphate. With
Is per cent acid phosphate selling at
$13 ton, 40 per cent one should bring
$50. Even at this figure the higher
priced article would be the most eco
nomical on account of freight, as 4
would be only one-third of that of the
lower grade goods. Another factor
comes, however, into the matter, which
is the additional cost of producing the
more concentrated article. An actual
pound Of available phosphoric
acid sells at higher and
"higher price as it becomes more and
more pure. While it is worth 4 cents a
pound in an ordinary "acid phosphate"
it sells for $3.50 pound in a perfectly
pure condition as used by chemists.
Cottonseed meal is one of the large
sources of nitrogen, yet as it is put upon
the market it only contains nitrogen
equivalent tos8 12 per cent of ammonia.
The raw cottOnseed itself contains a still
smaller percentage before the removal of
the hQlls and oil. This partial concen-
tration of nitrogen in the cottonseed
meal is too expensive to undertake for
fertilizing purposes alone. 1t is the ex-
traction of the valuable cottonseed Oil
upon which the industry chiefly depends
to make the business remune~ative. If
agriculturists could afford to use the
most concentrated ammoniates which 1t
is possible to produce, such am1noniates
could be made far cheaper from other
materials than cottonseed. Blood is Il
by-product from the slaughter houses,
and contains nitrogen equivalent to
about l6 per cent of ammonia, and while
higher per ton, usually costs. less per
pound for the nitrogen it contains than
,he ccttonseed meal. If cottonseed meal