The Vermont watchman. [volume] (Montpelier, Vt.) 1883-1911, 1886-12-01
Production of heterogeneous Plant Food
in the Soil.

The heterogeneous portions OF dead
plants and eXcremental matters which
are applied to the soil as fertilizers are
not at first in an available condition.
They have to undergo changes of form
and composition before the feeding
roots can take them up. The ultimate re-
suit of these changes is the production
of that class of salts called nitrates, or
compounds of nitric acid Under proper
conditions of moisture and temperature
these changes are always going on in
soils which contain dead organic mat
ter, vegetable or animal. In some
soils and under peculiar conditions nj
trate of soda is the salt formed, and
large quantities of this salt are extracted
from the soil, by teaching and evapo-
ration, in the dry territory lying be-
tween Peru and Chill. 1t is known
as soda saltpeter, or Chill saltpeter,
and is extensively used by fertil-
izer-makers, and by some farmers.
But under the most common con-
ditons nitrate of potash Common salt
peter) is the salt so produced, and its
production is slowly going on, when
the weather is sufficiently warm, in
every soil containing the requisite ma
terals, which are dead vegetable and
animal matter, with a little lime. In
very dry weather the saltpeterso formed,
if in sufficient quantity, will show on
the surface as a white deposit 1t con-
stitutes the most valuable of all fertiliz-
for all the elements of plant-food are
equally necessary to the growth of crops.
When our soils contain sufficient nj
trate of potash, nothing more is needed
to complete their fertility except proper
quantity of phosphoric acid in an avail
able form. Nitrate of potash and
soluble phosphate of lime constitute
together complete fertilizer, because
they furnish the four essentials of plant
food-nitrogen, potash, phosphoric acid
and lime. We say " FOUR but prob
ably sulphur is also essential-yet as
both sulphur and lime are usually pres
ent in all soils, and do not need to be
supplied artifcially, it is common to
mention the three which we are called
on to supply to our crops, viz. nitrogen,
potash and phosphoric acid.
Just how the nitrates are produced in
the soil Cor in the old process of salt
peter-making. which consisted in form
ing heaps of soil with animal matter
and lime, carefully mixed, and moist
ened) has been an unsolved problem.
But it is now believed that the neces-
sary changes are brought about by the
action of minute yeast-like plant
which spreads through the soil Cor
through the saltpeter-maker's heaps),
causing, in its growth, the changes
which conduce to notification q. e.,
niter-making.) AS long ago as 1882
Pasteur, the famous French scientist,
suggested the possibility of this, and in
1873 Muller, a German, advanced the
opinion that nitrifcation was due to
action of ferment. He based his
opinion upon the fact that solutions of
pure ammonia salts and of urea are
very stable, while the same bodies in
sewage are rapidly nitrifi ed-holding
that the difference was due to the pres
ence of ferment in the latter case.
In 1877, Schln sing and Muntz pub
lished the results of experiments which
indicated that Pasteur's suggestion and
Muller's opinion were correct, and that
nitrificaton might really be classed as
fermention. These eXperimenters were
engaged in investigating the oXidizing
effect of the soil upon sewage. They
filled glass tube one meter long with
mixture of quartzose sand and small
quantity of powdered limestone, and
caused sewage to filter slowly through
this artificial soil so that it occupied
eight days in passing through the tube.
For twenty days the sewage passed
through unaltered. Then nitrates began
to appear in it, and rapidly increased
in amount until all the nitrogen of the
filtrate was in this combination. If nj
trification is due to simple oxidation, it
is difficult to see why it was so slow in
commencing; but, if it is due to an or
ganism which required time TO develop
in the artificial soil, the delay is at once
explained.
The practical value of this dis
covery may not appear to be great to
the farmer, yet so far as he is enabled
to favor the growth of this nitrifying
plant in his tillage land it will be greatly
to his profit to do so. The conditions of
its growth are warmth, moisture and
air. The farmer cannot furnish the
first two, but by frequent culture at the
proper season he can furnish the latter,
without which the others do not work
effectively. The saltpeter-maker often
turns and mixes his heaps to air them,
and then carefully moistens them. The
farmer, by the frequent use of his till