Burlington weekly free press. [volume] (Burlington, Vt.) 1866-1928, 1896-03-05
THE SOIL AS A MINE.

Tnc SOIL is perhaps less a mine than a
natural soil fertility" | have read an
article by farmer-experts, whose names
appear even weekly in leading agricultural
Many and curious are the definitions of
laboratory; unquestionably, 1t engages
papers, in which the simple chemical an
alysis of a soil Is quoted to show that the
soil Is mine of the fertilizing principles,
so rich that a century of continuous crop
ping would be required to reach even mod
crate exhaustion.
many of the properties of both There can
he no questioning the fact that the aver
age soil contains certain quantities OF
nitrogen, potash and phosphoric acid, but
there Is "A very considerable doubt If the
farmer can afford TO mine for them. The
use of a soil as a laboratory is a different
matter and towards this use the success
full farmer of this age utilities the cheapest
and most effective forces-chemical man
ures.
The soil as a mine deserves a little fur
ther treatment here, for the progressive
farmer will want to know why the stores
of potash, etc, in the soil naturally, will
not aid vegetation as well as the same
materials in the shape of chemical salts
for which he must pay. The sole reason,
perhaps, is because these chemicals in the
soil are not available; that is. they are not
soluble in the soil-waters. AS a general
principle, 1t Is practically impossible to
get thorough distribution of the fertil-
zers in the soil, unless they are soluble in
the moisture of the soil and are through
this means brought within the reach of the
root hairs; when this is once accomplished
the plant makes use of the supply some
thing in the same manner that q pump
continues 10 draw water from a well
Solubility is the important property in
fertilizers and manures, and 10 mine them.
means to render them soluble. The or
binary chemical analysis of a soil does
not show soluble forms, as the acids used
in the determination are far more power
full than the soil in natural condition
can possibly supply. Analyses have been
made with an acid diluted to a point close
ly approaching actual soil conditions dur
Ing healthy plant growth, and the results
are striking.
The total nitrogen in the surface soil
was IL per cent, of which only i6 per cent
was found available for plant food; that
is, out of every 100 pounds of nitrogen in
the soil, but l6 pounds were of use in
promoting plant growth. The total pota sh
was found TO be go per cent, and the
available potash .053 per cent; of every 100
pounds of potash in the soil naturally, but
eight and a half pounds were available
The total phosphoric acid was found TO
lie .19l per cent. and the available Oii per
cent. from every 100 pounds of phosphoric
% pounds were found 10 be available as a
fertilizer.
These figures are important from the
fact, that they show the relative avail
ability of the manurial principles in the
soil, and 1t must be remembered that these
are the results of the soil operated as n
laboratory. and not merely teaching with
water. All three of the chief manurial
clements, nitrogen, potash and phosphoric
acid, when supplied to the soil, are either
taken up by plant growth, leached out
By drainage waters or take forms as in a
natural soil formation and become avail
able very very slowly.
1t will be we'll to place these determined
results side by side for comparison. In
fairly fertile soil, one ton of the surface
soil will contain:
Avail
Tdtal. able.
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iotasn''..'. '.''.............,l9S OF. II OF.