The Vermont watchman. [volume] (Montpelier, Vt.) 1883-1911, 1885-07-22
Are PhOsphates Really a Manure!

of mental awakening and business
progress among our farmers than the
intelligent interest they are taking in
the fertilizer problem. The general
lack among farmers of any elementary
training in agricultural chemistry is a
great hindrance in the way of fully I'M
derstanding the use and the profitable
application of chemical manures to
their crops. This should stimulate
them to educate their children well in
the natural sciences, for it is on this
basis that the farming of the future
must be established. We have several
times had the above question pro-
pounded to us by intelligent farmers.
AS we, besides editing this department,
have long been regular paid con-
tributor to such well-known journals as
the Ne,o York Examiner. the Rural
New Yorker, the Maine Farmer, the
Mirror and Farmer and the Home
Farm, we are pretty well known to the
agricultural public over considerable
region, and questions reach us almost
daily on subjects of agricultural inter-
est. In reply to the one put at the
head of this article we lately sent to the
Home Farm the following article, which
we here reprint, as we have had the
same question repeatedly from WATCH
\, " raoJarc l1t boyn not bofnro 20 yor,
the time necessary to answer it in de-
tail.
A Kennebec county correspondent
(whose note / enclose) sends me the
following questions, to be answered
through The Home Farm:
l. Are the phosphates really a ma
nure, or do they liberate plant food al
ready in the soil?"
2. " If they are really manure, are
present prices?"
An intelligent reply to the first ques-
tiCn requires, first, a definition of the
word A" manure" Worcester defines it,
broadly, as anything that fertilizes
the land" which would include water,
and even cultivation. But to the far
mer manure means plant food, and par
ticularly such plant food as must be
supplied by him to maintain his crops,
and cause them to bring forth abun-
dainty. Coming down to the details,
for which we are indebted to the re-
searches of the agricultural chemists,
manure is practically anything which
supplies to cultivated crops in an avail
able form the three e!ements-phospho-
rus, potassium and nitrogen. These
are the only elements demanded by
our crops that are ordinarily lacking in
land that has been for some time under
cultivation. They are all supplied by
animal dung, which has for ages been
known almost exclusively as " manure"
though all decaying animal and veget-
able matter has been long known to
have manurial value. Tested by this
definition, phosphate (Which is a
compound of phosphorus), though not
g manure" in the full sense in which
dung is manure, is yet a manurial
substance. Used alone upon soil des-
titute of available potash and available
nitrogen, phosphate would not pro-
duce crop, and would, indeed, appear
to have no favorable influence what
ever. But when phosphate is joined
with available potash and available nj
trogen, the compound is complete ma
nure, just the same as stable manure,
for it contains the same elements.
To the second clause of the first
question separate answer should be
given. l have no doubt, whatever,
that the ordinary complete fertilizer
made from an acid phosphate, potash
salts and animal nitrogen, or nitrous
salts, does, besides acting directly as
plant food, also act to liberate and make
available the plant food already in the
soil, but not available on account of its
insolubility, or its feeble sOlubility, in
the saltwater.
What does a barrel of an ordinary
commercial superphosphate contain?
The label on the package and the analy-
sis of the chemist says: " PhOsphoric
acid, in such and such forms, so much. y
Nitrogen, so much, equal to ammonia
so much" " Sulphate, muriate, OF
carbonate of potash, so much, equal to
absolute potash, so much"
But this is only partial analysis, its
percentages, added together, rarely
equallng one-third of the whole weight
n COlnplclc dlul SiS WOulu lcNcdl llldt
besides the above-named substances
the barrel would contain, to the extent
at least, of another third, sulphate OF
lime-that is, land plaster or gypsum
This is formed by the union of sui
phuric acid with the lime of the bones
or the phosphate rock, to which it was
applied. The other third of the barrels
contents is made up of some free sui
phuric acid, of moisture (rarely less
than twelve per cent of the whole
weight, of common salt (Which is al
ways mixed with the mineral potash
salts), and of sand and other liner
matters, associated with all the ma
terials used.
Now there can be no doubt that thu
free sulphuric acid, the plaster and thu
salt are all capable of imparting to tn,
saltwater greater dissolving powe
than it is naturally likely to possess
and in this way a commercial super
phosphate not only furnishes plant foo
directly to the crop, but also, in tn
| words of my correspondent, " liberate
plant food in the soil itself And this
, ! believe, is much more importan
function in superphosphate than it i
generally thought TO be. If two barrel
r of superphosphate are applied to a.
2 acre, this means at least two-thirds o