The Marietta journal. (Marietta, Ga.) 1918-1944, 1920-12-24
SOLUBLE ELEMENTS
MOST IMPORTANT
production Based on Liberation of
the Phosphorous and Potash Into
Right Plant Food.

The frequent requests made for
the examination of soil samples evil
dence a general misconception of the
value of soil analysis. The preva-
lent impression among farmers seems
TO be that such an analysis will dir
Getty indicate the need of specific
fertilizer treatment. Soil ANALYSIS is
important; but quantity of plant food
III the soil is not always the control
ing factor of crop production. Ply
slclal character, subsoil, climatic con-
dltlons, etc, are all-important in in
fluencing yields.
In the chemical analysis of soil the
method now generally used is to dis
solve the sample and determine the
total amount of the various plant
food elements. An acre is consider
ed to contain two million pounds of
soil in the top six inches. An applica-
ton of fertilizer containing 200
pounds of potash wiuld only increase
the amount of potash in an acre by
one hundredth per cent (0.01 %)- a
variation we'll within the limits of
error in chemical analysis; yet appli-
cation of potash at this rate would
supply any demand for such reasons
that chemical analysis is of no con-
siderable value as an indication of
the immediate need of crop for
particular fertilizing element.
Certainly an examination Of the
soil would show the relative deficien-
cy or sufficiency of any element, but
the knowledge would not be a safe
guide for fertilizer treatment for the
next crop. In longtime system of
fertilizing and soil building know
ledge Of the composition of the soil
is indispensable, but is not sufficient
in itself. While the total amount of
any one element present is often high
the land will readily respond to an
application of this element. Thus an
application of few pounds of soluble
potash to a sell containing $4,000
pounds of potash to the acre resulted
in increased crop production. In the
same soil PHOSPHORUS was deficient,
only 100 pounds per acre being pres
emit. Evidently the system of treat
ment should include the liberation of
available potash from such an enor-
nous supply, as well as the addition
of PHOSPHORUS to the soil.
At the N. Y. Experiment Station it
has been found from close study of
figures showing the percentages of
nitrogen, PHOSPHORUS, and calcium
oxides. in soils from various plats.
that there is no relation between
these percentages and the productiv
ity of the plats, nor was there any in
dication of appreciate changes in the
composition of the soil after seven
teen years of greatly unlike treat
ment in the application of manure
and fertilizers in cropping.
Chemical analyses of soils ore in
dispensible to the purpose Of scien-
tific investigation and it has only been
through their aid that the present
knowledge of agriculture has been
accululated. When differences in
production are observed in soils 9TH
erwise similar, analysis would pro-
badly reveal the reason and although
the expense is considerable it would
then be justified. Promiscuous an
alysis of individual samples however
is not advisable, since it is not yet
possible to measure accurately the
fertility of soil by that means.