The Portland daily press., 1876-04-03
THE FARM AND HOUSEHOLD.
Gypsum.

o.. -... ..-r... Gypsum.
The city OF Paris is built upon basin
which contains in its geological formations
two strata famous in commerce-one for fur
nishing the stone OF which the city is built,
the other for the fine gypsum from which
the Plaster of Paris is made. This was OBJ
tanned by burning the stone until reduced to
a powder, and this calcined plaster was used
for stucco work, and the smooth finish of
the walls and ceilings of interiors. So long
as this salt was taken from this original de-
post and used for ornamen tai purposes, its
name was appropriate; but when it is brought
from other localities and only applied TO the
earth as fertilizer, it is properly described
as gypsum, or sulphate of lime.
Although lis value to farmers seems to
have been recognized by Virgil, and it was
actually used by the first inhabitants Of
Britain, men of science were not able to dis
tinguish it from limestone, or other calca-
reous matter, and it was not until the middle
of the eighteenth century that in its simple
state it was introduced as manure, and
then by the Germans.
When in state OF purity it is composed of
43 parts sulphuric acid, SO Of lime and "a of
water-usually however, it is found in COM
bination with other substances containing
iron enough TO darken its color.
Probably no artificial fertilizer can be 80
generally and so easily obtained as this, and
upon some soils no one produces more posi-
tive hanafite opd yot hv m apu pro nfical mon
it is denounced as worthless, and many sci
entifc men seem unable to discover its bene-
fetal modes of operation.
Some Writers assert that its mode of action
is to furnish direct food to plants, and there
fore it need not he used for those plants into
whose composition il does not enter. Chem
ical analysis has settled that clover contains
this ingredient, and experience also demon
strates that it always receives benefit from
an application of the fertilizer to the soil. If
as they state, wheat, barley. oats, beans and
peas do not contain trace of this salt, then
the farmer need not waste his time and
money in giving it to the.soil on which they
grow unless he believes that it plays USE
full part in unlocking plant food from other
unwilling substances. As analysis shows
that an ordinary crop of clover usually con-
tains from one hundred and fifty to two hun
dred pounds of sulphate OF lime per acre, so
also the careful experience of practical men
demonstrates that it is useless to apply any
more than this amount to their fields
Whenever it is applied to certain lands or
crops without producing any perceptible
effect it may be safe to conclude, without the
expense of analyzing the soil, that it already
contains gypsum, or else lime and sulphur as
simple elements. So likewise whenever a
field ceases to produce clover, even when
manure from the barn yard is largely applied,
the obvious inference is that this important
constituent should be Immediately supplied.
Another class of scientific men advocate
the use of gypsum, not only because it furn-
ishes food for plants to soil which never con-
tanned it, and to those which have been ex-
haustee by cropping; but also, because it
fixes the ammonia of the atmosphere, and
lays it up in store for the future use of plants
by decomposing the carbonate of ammonia
contained in rain water, and making soluble
sulphate of ammonia and carbonate of lime.
As this sulphate is not volatile at the ordina-
ry temperatures, 1t thus retains the ammonia
TO be used when called for. This new COM
bination takes place, because ammonia and
sulpheric acid have greater mutual attrac-
tlon, than ammonia and carbonic acid. The
ammonia, therefore, leaves the carbonic acid
with which it has been united, and unites
with sulphuric acid, to form sulphate of am
monia; and the lime deprived of the sui
phuric acid, unites with carbonic acid, to
form carbonate Of lime. This carbonate of
ammonia, with which gypsum makes this
new combination. either comes from the at
mosphere, where it is.formed by the union of
carbonic acid with the ammonia which is al
ways forming by the union of nitrogen and
hydrogen-or else from the earth.
To Liebig, belongs the credit of discovering
what Sir Humphrey Davy and other eminent
chemists had failed to do, the presence of
ammonia in the atmosphere, In accounting
for the value of gypsum as fertilizer, he
thus remarks: ''The evident influence of gyp.
sum upon the growth of grasses-the strik-
ing fertility and luxuriance of meadow up
on which it is strewed-depends only upon
its fixing in the soil the ammonia of the at
mosphere, which would otherwise be volatil-
lied with the water which evaporates. The
carbonate of ammonia contained in rain wa
ter is decomposed by gypsum, in precisely
the same manner as in the manufacture of
sal ammoniac. Soluble sulphate of ammo
mia, and carbonate of lime are formed, and
this salt of ammonia possessing no vslat-
itity, is consequently retained in the
soil. All the gypsum gradually disap-
pears, but its action upon the
carbonate of ammonia continues as long as
trace of it exists. Water is absolutely nec-
essary to effect the decomposition of the gyp.
sum, ON account of its difficult solubility-
one part requires four hundred of water for
solution-and also to assist in the absorption
of the sulphate of ammonia by the plants;
HENCE it happens that the influence of gyp-
sum is not observable on dry fields and mead
ows. The decomposition Of gypsum by car.
Donate of ammonia does not take place in
simultaneously, on the contrary it proceeds
very gradually; and this explains why the
action of the gypsum lasts for several years."
Upon the same theory we account for the
value of gypsum when used in stables, and
thus by their simple and inexpensive combi-
nation the health of man and beast is pro-
NOTED and the value of the manure in 9.
creased.
The beneficial action of ashes upon the
soil is attributed not only to the potash, but
to the sulphate of lime therein contained.
In peat ashes this is largely the case, and in
coal ashes most of the benefit may result
from the ten per cent. of gypsum it contains.
Whenever gypsum is present in the soil, it is
suggested by some writers, that it increases
the solubility of potash, which is frequently
found in forms not easily soluble, and there
fore not easily appropriated by the plant.
Also, it assiats the plant in taking up an adj
ditional quantity of potash, which otherwise
it could not do. Gypsum also brings other
elements of plant-food, such as phosphoric
acid, and masnesa into solution, so that it
may give aid TO the plant in obtaining its