Oxford Democrat. [volume] (Paris, Me.) 1833-1933, 1918-04-09
Soil Analysis: Physical and Chemical.

STANLEY B. Sink. instructor In Agronomy,
Soils Division. University Of Maine.)
So much has been said and written
about the chemical analysis of soil that
IL is sometimes thought to be the only
diagnosis for all the ills of the soil.
While 1t is of value to the teacher, in
vestigator and experimenter for estab-
fishing the basic and fundamental facts
of soil composition and the abundance
or scarcity Of available or unavailable
plant foods; to the farmer who is inter-
estsd only In the crop producing power
of the soil, chemical analysis may or
may not be an index to soil fertility.
There are SO many other factors like
rainfall, temperature, drainage, soil
texture and structure, etc., besides Its
chemical makeup that 90 to make up
the fertility of soil that 1t is evident
that even though soil be we'll supplied
with the necessary elements of plant
growth it yet may not be a fertile soil.
As q rule, however, . good productive
soil will show q greater total amount OF
plant food than will poor soil. A good
clay loan of New York state showed on
analysis to have 1880 lbs. OF nitrogen,
1850 lbs. of phosphorus and 2S, 400 lbs.
of potassium in the upper 8 2-S inches of
soil per acre. Good wheat land In
Michigan shows 1900 lbs. nitrogen,
5000 lbs. phos pborus and 1880 lbs. Of
potash per acre 6 23 inches, while the
poorer Jack Pine soil Of the latter state
shows but 740 lbs. of nitrogen, 300 lbs.
phosphorus and 1900 lbs. of potassium.
The above figures are significant and do
show differences in soil types that are
borne out in their crop producing power.
The above figures are the result OF q
large number of analyses, and averages
had to be taken. A reasonable argument
against chemical analysis for determin-
ing the fertility of any particular soil by
merely chemical analysis is that so small
sample Of soil Is taken for the
determination that IL is impossible to
get a representative sample Of any
particular soil type. This is quite true,
unless large number of samples are
taken and q mixture made and finely
ground together. Even then the error un-
avoidably made in the extremely delicate
weighings in the analysis, may be great
or than the plant food required to grow
. crop.
The type of q soil is determined by q
ply sical or mechanical analysis, and to
the practical farmer that ID the more
important. If the type 10 established,
more is then known about Its crop
adaptation, and, to ono who 10 familiar
with the chemical analysis of the typical
soil types, more about It's fertilizer re-
quirements will also be known. A
chemical analysis alone without any
knowledge of the soil type, structure,
drainage, etc., would be OF little value In
either determining the crop adaptations
or fertilizer requirements. Mechanical
analysis reveals whether the soil In
question 10 early or late, clay, muck.
loan, or sand or any combination OF
textures, the amount of organic matter,
ease of drainage and tillsge and many
other things that would be moro valu-
able to know about farm under con-
sideratiOn than its bare chemical analy-
sis.
When the chemist finds an exact way
of Initiating natures way OF getting
plant food from the soil and then de-
terminse In an easy and inexpensive
way, the amount plant can get from
the soil In . growing period; We shall
have reached the path that leads to the
solution of many soil fertility problems.