Lincoln County leader. [volume] (Toledo, Lincoln County, Or.) 1893-1987, 1912-01-26
GROUND LIMESTONE: WHAT is
1T AND WHAT is ITS ACTION
ON THE SOIL?
(By Professor H. V. Tartar, of the
Department of Chemistry, o. A. c.

(By Professor H. V. Tartar, of the
Department of Chemistry, o. A. c.
Oregon Agricultural College, Cor
Wallis, Ore.-Recently numerous in
quiries have come to the writer re-
garding the nature and the agricul-
tural use of ground limestone. These
Inquiries have shown that some farm
ers of the state have obtained erron-
eous ideas regarding this material. 1t
Is with a view of correcting these
mistaken ideas that this article has
been written.
Limestone is more or less impure
form of carbonate of lime. Carbonate
of lime is a chemical compound con-
tanning 40 per cent of calcium, II per
cent of carbon and 4S per cent of
oxygen. AS it occurs in nature it is
mixed with some impurities such as
sand, iron, alumina, phosphates and
often a considerable quantity of mag
nesium carbonate.
When this compound calcium is
heated to bright redness it decom-
poses into two compounds known
chemically as calcium oxid, a solid
substance, and carbon dioxide, a gas
The commercial form of calcium
oxide is ordinary quick lime" 1t is
ceally lime stone from which all the
carbon and two-thirds of the oxygen
present have been driven off in gase-
1us form by the aid of heat, the
quick lime remaining being about
Sc per cent of the original amount
If limestone used.
When exposed to the moisture of
he air or soil quicklime rapidly takes
Up water combining with it to form
L chemical compound, calcium hy-
lroxide, which is mere water slaked
ime. This compound formed by the
hitting of quick lime and water is
the same whether the slaking takes
,lace rapidly or slowly.
When air slaked lime is exposed
n the air or soil, carbon dioxid (the
same gas which is given off when
luick lime is formed from limestone)
gradually absorbed and calcium
carbonate is again formed. The thor
)ughly air slaked lime is exactly the
same material as finely ground lime
stone. 1t is evident then that no
natter whether we apply quick lime,
water slaked lime, air slaked lime or
,TOuuu llHo otOuC, IuC pOhCht w
lived during the subsequent months
,r years is due to one compound,
calcium carbonate.
Because of the fact that carbonate
If lime is the final substance formed
when quick lime or slaked lime are
ldded to soil, it would seem advisa-
ble to use finely ground limestone
lime carbonate) in the beginning.
The limestone is also cheaper be-
cause the cost of burning has been
eliminated; it's action on the organic
matter of the soil is less caustic; it
is more easily handled than quick
lime or slaked lime. For these rea-
sons finely ground limestone has
come into considerable use in several
of our eastern states.
Lime is an essential element of
plant food for all higher plants. 1t
seems to be especially necessary in
the leaves and stems for the proper
elaboration of starch. The total
amount needed is small, varying for
different plants, and the supply in
the average soil is ample for those
needs. Very rarely is it necessary
to add lime to soil simply to
serve as plant food. For this reason
lime has not been recognized as a
normal fertilizer constituent, like
nitrogen, phosphorus or potassium; 1t
serves as an amendment or supple
ment to the soil mechanism
The chief reason for applying lime
stone to soils is to correct or neu'
tralize the free acids in the soil. In
the decomposition and fermentation
of the organic matter of the soil
chemical changes take place which
are accompanied by the formation
of certain acids such as carbonic
acid, nitric acid, and various organic
acids. This formation of acids is
analogous to the formation of Tactic
acid in the souring of. milk, of acetic
acid in vinegar from apple juice, and
of the various acids in ensilage and
sauerkraut. When there is no car.
Donate of lime present in the soil
much of these acids usually remain
in the free or uncombined state. Ger
tain farm crops, such as clover, al
sike, COW peas, soy beans and most
valuable legumes do not thrive well
on soils which contain much free
acid. These crops can be often made
to grow, it is true, on acid soils by
liberal application of farm manure
and other fertilizers. but under these
conditions the nitrogen gathering
bacteria of such legumes do not mul
tiply and develop as they should
The presence of acids is inimical tc
the action of the legume in taking
up atmospheric nitrogen, one of the
main functions Of this kind of plants
in soil improvement. When GROUND
limestone is added to such soils II
chemically reacts with the acidic sub
stances present to form neutral ant
harmless compounds. 1t is to this
neutrallzing effect that ground lime
stone owes most Of its beneficial eff
fects on certain crops.
Again, in the decomposition of the
organic matter of the soil chemica
changes are brought about through
certain bacteria, known as nitrifyins
bacteria, whereby insoluble organic
ritraOap fa,r,n mamma ond plon