Durango semi-weekly herald., 1905-12-25
SOIL ANALYSIS.

tJ. II. I1nSley IN Aztec lndeS.)
The experimental station at Mesila
Park occasionally receives samples Of
soil. often less than an ounce. with
the request that 1t be analyzed and
the sender informed as to its fertility
and the crops to which it is best
adapted. Ability to comply with such
requests is very much to be desired
but in spite OF all the study that has
been devoted to soils from the vari-
Gus view points. 1t is still practically
impossible to tell much about the fer
tility Of soil or its adaptability to
certain crops from the examination of
small sample of the soil.
There are many factors that enter
into successful crop production, but
they may be roughly grouped under
climate and soil. There may be an
abundance OF plant food in the soil
and yet a crop may fail to grow be-
cause Of insufficient moisture, too
much moisture, too high or too low a
temperature.
The soil sample. of course, does not
tell anything in regard to the climatic
conditions. and we must learn these
by observation or otherwise. Assume
that we know the climatic conditions.
what data concerning the soil factors
can we derive from the sample? The
nature of the sample itself is an all
important matter.
The sample, whether large or small
must be representative of the soil in
question. This can be most nearly
approximated by taking samples from
number of points in the field and
mixing them into a composite sample
from which the sample for examina-
ton may be drawn. One will readily
see that the chances are poor that a
composite sample will accurately rep
resent any large area. What then
single small sample?
The fertility depends on, among
other factors, the amount of readily
soluble plant food, and the physical
Characters Of the sell, such as fine.
ness Of its particles and the arran ge-
ment of these particles allow ing lree
circulation of air and water as wei as
allowing roots to penetrate readily.
The idea here suggests itself that VT
must not only know these points
about the surface but to as great n
depth as the roots are liable to vene.
trate.
From proper sample something
can be learned in regard to the case
or difficulty of handling the soil, the
q in,
irrigation. In general way the ma.
ture OF the crop may be indicated, pro.
vided the climatic factors are not nm
favorable. Certain crops do best on
heavy soils and others on lighter, bet
ter drained soils; but while this is
true. other factors may be either so
favorable or unfavorable that the in
huence of texture may almost disap.
pear.
The first question that suggests It.
self to the average mind is that of
plant food. Is there plenty OF avail. |
able plant food? 1t is supposed by
many that this question can be read. |
iiy answered by a chemical analysis:
nut as yet the chemists do not feel
that their analysis gives a satisfactory
answer to the question. The plant
food in soil may be divided into fiat
portion which becomes dissolved dnr. |
ing the growth of the crop and that |
winch does not The principal prop. |
lem In sci analysis has been to fui |
solvent which would dissolve the
materials In the proportion in wnich
they are dissolved by the plants. II
Is comparatively easy to make a com
piete analysis OF the soil; but such an
analysis gives hut little Information
as to the amount OF materials that a
plant can take from the soil: and,
while many solvents have been tried
with the hope that the amount of food
shown would correspond with the
growth OF crops on the sell satisfac-
ory solvent has not vet been found
Another reason for this unsatisfac.
ory condition is that the weight of
Material removed from an acre of soil
" one crop is so small in conpari.
on with the weight of soil on an acre Z
o depth of two or three feet as to
lie within the limits of error of anal.
Sis. on two soils, one might contain
nough soluble food for. say n crop of
'heat. and the other not enough. and d
ct the analysis be practically the n