The progressive farmer. [volume] (Winston, N.C.) 1886-1904, 1896-12-22
HORTICULTURE
THE DIssOLvING POWER OF
ROOTS.

That all cultivated plants take their
food only in the form of solution, and
this almost exclusively directly from
the soil by means of their roots, are
facts generally recognized. The meth
DDS by which the result is accomplished
are, however, comparatively unknown,
yet their practical bearing on the prob
lem of plant nutrition and food supply
is of vital significance.
Water passes through the soil taking
but little soil matter withit in solution,
showing that the plant food Constitu
ente are comparatively insoluble in
water. Much Of the material added to
soils as sources of fertility is likewise
only partly soluble in the moving
waters Of the soil It is therefore ap
parent that the elements of nutrition
either naturally or art.ficially pres
ent in the soil would be compare
lively inaccessible to the growing crop,
but would remain locked up in the soil,
were the dissolving power Of water the
only available means for its conversion
into solution and thus becoming assim
liable to the plant.
The roots Of plants, however, are en-
dowed with the power Of d~issolving
their own food when not other wise
available. The roots possess the prop
erty of securing an organic acid which
being excluded from the growing tissue
comes in contact with the iDsoluble in
gradients of the surrounding soil and
acts as a solvent on the same, much IS
the gastric juice of animals acts on the
food in their stomechs, rendering the
food constituents soluble, and reducing
to solution so that it is readily taken
up and entering the plant through the
same roots. is assimilated and becomes
the new tissue in the growth and de
velopment of the crop. The practical
bearing of this fact lies in the fact that
the most important nutritive ingredi
ents of the soil exist very largely in
combinations not otherwise sufficiently
soluble to meet the demands of the
crop during the season of rapid growth.
The Importance of this condition is
still further enhanced by the fact that
ven materials added to the soil in the
form of soluble fertilizers are to a very
considerable degree transformed in the
soil into forms not soluble in soil
waters.
The two least abundant, and there
fore most important, mineral soil con.
stituents are phosphoric acid and pot
ash, and they are the only u e for
which crops must chiefly depend on
artificial eupply. These tWo substances,
an acid and a base, would naturally
unite to foIm phosphate of potash
This is a very soluble substance and
were nothing to interfere by changing
its character, it would be rapidly dis
solved in the soil water and be washed
away faster than it could be taken up
by the plant; and thus these indispens
able plant nutrients would be lost to
the crop. Nature has provided, how
ever, that they undergo q re combina-
tion in the soil, each uniting with other
soil cor stituents to form insoluble com
pounds.
These latter, however, though not
readily dissolved by soil water, are
chemically soluble, and thus available
to the crop. TIE solvent secrtt8d by
the roots is the most active agent il
efecting this result, and therefore it is
clear that the diesolving power of the
root is the most potent factor in rem
dering soil ingredients available as
plant food. An equally important fact
Is the truth that this same property is
Indirectly responsible for the conse1va
ticn In the soil Of the mineral food in
gradients till required by the crop, IN
stead of passing away in the percolaV
ing water, the most importanto OF u hico,
potash, exists in quantities hardly
equal to even the present demand.-H
E Stockbridge. Farm News.