The Florida agriculturist. [volume] (DeLand, Fla.) 1878-1911, 1895-01-30
The Use of Phosphate.


Florida phosphate was doomed as com,
plete fertilizer, and those who used it as
such were of course disappointed.
From the following report of field ex-
periments by Director Geo. HI. Cook of
the New Jersey Experiment Station it
would seem as if there was considerable
virtue in Florida phosphate if properly
handled. He says:
"Of these only the trials of different forms
OF phosphoric acid possess any interest at this
time Phosphate Of four different degrees of solu
blity is now to be found in the fertilizer markets.
First that which is soluble in water distilled)
the ordinary superphosphates; second that
which is not soluble in water (distilIed), but is
soluble in ammonia citrate solution OF a certain
temperature the ordinary reverted phosphate;
third that which requires higher temperature
of the citrate for it's solution, found in fer
tilizer insoluble phosphate of alumina; and
fourth, that which is insoluble under any of
these conditions, and is found in the so-called
floats or very finely powdered South Caro-
lima rock phosphate, not treated at all with
acid to make it soluble. The more difficult the
soubity of these phosphates the less their price;
while, on the other hand it is claimed that under
certain and not unusual conditions the lower
priced ones will give the largest return in in
creased crops. A more useful work could hardly
be undertaken by the experiment station than a
series of field experiments for the purpose of
testing these claims. In the trials begun in 1885
at the station, in the of five experiments
out of the eight on different farms, the phos-
phate being used with potash and nitrogen
compounds, the increase of crop greater
with the more insouble phosphates than with
the more expensive superphOsphates; and that
in these five cases. the floats the cheapest Of
all, did the best work goes a little way, at
least, toward showing that the superphosphate |
may have had it's day. Sandy loans, sandy |
clays and limestone soils were those on which |
the more insolubleforms of phosphate gave such
good results
"a bulletin OF the Pennsylvania state college
experiment station gives the results of expert
ments made with phosphates in a four crop ro-
tation in the years 1887 the first years crop
being grown without manure to determine the
relative fertility of the several plots. The plots
were twelve in number, each of them one-twefth
of an acre in extent, and the soil is what is
ally called limestone clay.
"Oats were grown in 1883, and the product
showed considerable varl alton in the fertility of
the several plots. Taking 100 the average of
all, they ranged from 9l.62 to 114,52, eight being
under the average and four over it. The rotation
was in the order of wheat, grass, corn and oats,
and the fertilizers applied to wheat and corn
only-the grass and oats getting the residual eff
fects. Two plots were unmanured throughout
the experiment., and from the results of these
value of the fertilizers was computed The
periments were made to study the effects of diff
ferent forms of phosphoric acid; and to guard
against failure from lack of any of the elements
of plant food, each of the plats except the two
unmanured ones was treated to 200 pounds oi
muriate of potash and 24O pounds OF suphate of
ammonia per They thus supplied
with nitrogen. potash, sulphuric acid and chic
rine, while the limestone soil contained excess
of lime, magnesia and iron above what the crops
could possibly use Two of the plots received
other manuring and the remaining eight
were treated as follows:
81. Two hundred pounds dissolved bone
black, the phosphoric acid largely soluble.
- Two hundred pounds dissolved bone
black previously treated with lime; phosphoric
acid reverted
"3 One hundred and fifty pounds fine ground
bone.
a. One hundred and fifty pounds South
Carolina phospha tes, phosphoric acid largely in
soluble
''These fertilizers were all standard articles of
trade Now for the results of the fifty-six single
ses recorded; thirty-six show unuistakable
gain resulting from the nse of phOsphoric acid,