Alexandria gazette. [volume] (Alexandria, D.C.) 1834-1974, 1883-12-24
THE TESTIMONY OF EXPERIMENTS
IN FAVOR OF UNACIDULATED
PHOSPHATES
ALEXANDRIA, Va, Dec. %, 1885.

ALEXANDRIA, Va, Dec. %, 1855.
TO tho editor of the alexandria Gazette:
Knowing the great interest you take in
the important question now being so earn
estly examined by the practical farmers Of
this country and Enrope-viz: Is sulphuric
acid really necessary in the preparation Of
phosphate as Il fertilizer? have collected
n few extracts from what has been lately
published abroad, and submit them for
YOUR perusal. Our Prof Page, of the Uni
University of Virginia, has recently told us
'!sulphuric acid is a needless expense, nor
do | think it can be shown that superphos.
phates for example, dissolved S. {. Bone
are naturally more speedy in their effects
than undssolved phosphates if very finely
divided.n Prof Voelcker, the chemist Of
the Royal Agricultural Society Of England,
and one of the most distinguished men in
his profession has lately written: 'Phos-
phoric acid so largely required by grain and
grass, is usually found in the form of phos-
phate Of lime, which is almost insoluble in
water, but rendered available by the natu
raj agencies at work in the soil. 1t is often
treated with sulphuric acid TO change IL
from It's original insolubie into the soluble
form, the only advantage of which is the
acid more finely dividing the phosphate,
allows the rain more equally to distribute
it in the soil: but the acid must be again
preciptated and rendered insolublc before il
can be assimiiatcd by the plant. 1t is only
this more intimate division and distribution
for the subsequent precipitation that con-
stitutes the advantage Of more rapid ac-
ton of an acidulated over an unacidulated
one"
Mr.. Arthur Guerard of the Royal School
of Mines, London, in a phamphlet last win
ter, contributed the following interesting
statement the result OF many experiments:
"If YOU examine tho roots Of - plant under Il
microscope, they will be found to consist o!
innumerable cells, each covered with thin
skin and containing and acid fluid. BY
chemical law, an acid will always combine
with 4 base hence, when any alkaline plan!
food, as phosphate or carbonate of lime in ;t
line state OF division, is brought into CON
tact with the fine cells of the plant root, the
acid in the cell at once overcomes the ob-
stacle of the ipclosing skin, and absorhs the
basic earth. Consider the countless lnyrlads
of the living plant feeding organs extending
their iibrls in every direction, penetrating
often several feet into the soil, and we have
an idea Of the enormous forces they have at
work. 1t is evident that The plants have the
power Of extracting their food Immediately
from those portions OF the soil which are III
direct contact with their absorbant surfaces;
that is, when this food is in Il very fine state
of mechanical division. Forty years ago,
LieDig made the assumption that this
mineral plant food to be available, must be
soluble in water. This assumption then
universally accepted on faith, caused the
universal treatment of these phosphates
with sulphuric acid, and their commercial
value TO be estimated by the amount of
phosphate of lime present which was soluble
in water Now if this assumption Is not
true, and finely ground phosphate is
available, why should we pay for supcrphos-
phate to perform junction for which nature
has so amply provided il we only use finely
ground phosphate at one-balf the cost.
The insoluable phosphates need only TO be
ground to fine powder and mixed in the
soil. the plant then assisted by the action of
the weather, will convert with acid from
natures own acid chambers as mich Of this
insoluable into soluble phosphate as 1t re-
uuires The problem then resolves itself
into purely mechanical one, viz: 10 grind
into a state of division fine enough to be
assimilated by the plant This problem has
now been satisfactorily solved by an attrl-
tion mill, invented by Mr.. Due, of Charles
ton it reduces phosphate rocks to an i'm
palpable powder, showing (under the NIL
croscope) 10000 particles to the liner inch
| This degree Of inencss, which cannot be
obtained with the burr stones, is essential
for producing the complete manurlal effect,
| and the experiments on crops IN South
Carolina prove its effects. The report of
prof. Jameson to the Aberdeenshire Agri-
| cultural Society, an association of noblemen
and gentlemen of Aberdeen, Scotland, on
the results of several years experiments,
made to test the comparative value OF
soluble and insoluble phosphates, declares
"that soluble phosphate is not superior in
effect to insoluble, such rs S. c. phosphate,
| if the latter be in finely disaggregated
form;' The Scotch are good farmers, and
proverbially known as a shrewd 'canny Jotk;;'
| their confirmation may be taken asan answer
to the practical side Of the question.
In June 1851, at the International Con-
gress of Agricultural experimental stations,
held in Paris, Herr Maercker of the Univer-
sity of Halle, Saxony, reported 'preciplta-
| ted phosphate of lime employed in the same
quantity AS soluble phosphate on average
soils has shown itself equal to the soluble
phosphate" On this report Monsieur
Grandean, Commissary General of the Con.
gress remarks These conclusions resem.
Bile those have reached after eight years
experiments in France, as Herr Maercker
until recently was the most ardent adver-
sarv Of the value of precipitated phosphates
as compared with soluble, we rejoice to find
him now gracefully supporting conclusions
Numerically opposed to principals he has
always heretofore maintained" The agrri,,
culturists of France have for some time held
that soluble and insoluble phosphates should
be nut upon the same footing; that they