Shenandoah herald. [volume] (Woodstock, Va.) 1865-1974, 1877-08-08
FARM and FlREsIDE.l
Silica In Plant Growth.

A writer in the Country Gentleman
has just been reading Johnson's 'sHsw
Crops Crow" and is surprised to learn
that the old notion, that silica was
necessary to plant growth, has been
exploded for the last fifteen years,
though the report has but just reached
him. In contradiction OF facts, he
quotes old suggestions. Professor
johnson, in subsequent issue, sits
down rather heavy upon the New
Hampshire savant, whose knowledge of
agricultural chemistry does not even
equal mediocrlty.
'Mr. B. asserts that the maize kerr
nels produced by Sachs that contained
no silica were imperfect; perfect kerr
nels of our northern corn are always
covered with glazing of potash and
Silica"
In reply Professor johnson says:
Does Mr.. B. know such to be fact,
or is the statement only a specimen of
what he has always supposed to be
true? The average content of silica in
the grain of field grown Indian corn is
parts in 10000, which amounts to
ore pound Of silica in 1888 pounds, or
60 bushels. This for a glazing is rather
thin! But in fact there is no glazing
of silica and potash in any corn. The
cuticle of Indian corn is undoubtedly no
richer in silica than the bran of wheat,
and the latter contains no greater pro-
portion than is found in the centre of
the kernel. Much Of the silica reported
in our analyses of cereal grams, I'M.
questionably comes from minute par
tlcles of sand or soil which adhere
mechanically to the kernels.
As to whether the canto tree. the
bamboo and the securing rush, could be
grown in soil, or water, without silica,
Mr.. Bartlett opines not. For me it is
easy to believe that these plants can
be grown without silica. If wheat.
oats, rye, barley and maize have been
grown and are now growing without
silica, as is the fact, why not cante,
bamboo and rush! Whether the rush
without silica would serve for securing
may well be doubted.
It has ''always been supposed" that
the salt worts (Plantago martina.
GlauX martina, Salicornia herbacea),
which are found on the shores of the
ocean and Of salt lakes, always contain,
and absolutely require salt for their
nutrition. Late observations and ex-
periments have demonstrated that such
is not the case. These plants have
been raised from the seed by H. Hotf-
man, without any salt whatever, and it
appears that they are commonly found
in salt places because they endure salt,
and not because they need it. But al.
though silica is not indispensable to the
nutrition and growth of plants, it may
have its uses ); and some experiments
that have been made since "How
Crops Grow" was published, indicate
that such is decidedly the case.
Functions of siIiea-Potash.
A function of silica in cereals appears
to be to favor uniform ripening Of the
crop. 1t its absence these plants con-
tinued ito run to straw" and filing out
Of the kernels is delayed. 1t is sup
posed" that the silica which in field
culture accumulates in the leaves. di.
minishes their vitality. and determines
more rapid flow Of juices to the seeds, -
with the result that they ripen sooner,
but this theory may be no better than
Davy's supposition tina. silica strength.
ems the straw. The facts are, that it
has been observed in water culture, that
without silica the cerials rarely ripen
uniformly, and take up larger ouanti-
ties Of other mineral matters than
happens in presence Of silica.
Had | known these facts in 1868.
should not have written, ''Silica is not
indispensable to crops" but silica is not
indispensable to the growth of plants.
should have said that silica is proba-
bly, necessary to crops, by checking too
prolonged vegetative development, and
thereby insuring equal and early seed
production.
AS to the notion that potash facili-
tates the entrance Of silica into plants, it
is manifestly without foundation, and
for the reason that in the soil. silica is a
hundredfold more abundant and decid-
eddy more soluble than potash. If Mr..
Bartlett will look at the analyses of
rain water, and at the table Of mat
tiers dissolved by water from various
SOILS" on PIP. 3l0-3l5 of Glow Crops
Feed" he will see that with the excep-
ton of peat, nearly all soils, and espec-
tally good soils, yield more silica than
potash 70 water.
Prof. j. F. w. Johnston's faith that
silica is essential to crops, led him to
cause various trials to be made with
soluble silicates as fertilizer. but the
results were quite uniformly negative.
The fact IS, that while in good soils
silica Is more abundant in the saltwater
than potash, in poor soils, where soluble
potash is often deficient, soluble silica
is still abundant. The statements
quoted by Mr.. Bartlett that pure silica
is insoluble in water, but when fused
with potash, readily dissolves, is quite
true. In the soil, however, fusion at a
red heat cannot occur, and the fact has
no application to agriculture. There
are, however, various forms of ''pure
Silica" and some of them dissolve
freely in water. (How Crops Grow,
PIP. l2l and 1927 The chemistry OF
silica is somewhat complicated, and
its relations to potash are quite chang.
ed, when lime, iron and the other soil
elements come into play. If to a clear
solution Of silica in potash, as of potash
silica, large quantities oflime, oxide of
iron or alumina be added, an insoluble
compound of all these substances is
formed. If solution of carbonate of
potash is mixed with a soil, in such
small proportion as is suitable for a
fertilizer. not only is not silica made
more abundantly soluble by the potash.
but the potash is ''fxed'' in state of
relative insolubility by the silica or sill
cate which are the basis of all good soils.
Liebig, in giving an account of his ex-
periments on the absorptive power of
soils, says, "a clay or lime soil with
drew from solution of potash-silicate.
both silica and potash; a soil very rich
IN humus, extracted the potash and left
the silica in solution" Signed.
S. W. JOHNSON.
FIRM BUTTER WITHOUT Ice. From