The Mena weekly star. (Mena, Ark.) 1904-1977, 1911-11-30
WEEKLY LETTER
ON FERTILIZERS
State Chemist DIR. C. C. Hoffman
Gives Some Suggestions Con-
corning Improvement
OF the Soil.

Fertilizers: Their Relation to
Improvement of Soils" is the title
of the first of series of weekly
letters prepared by State Chemist
c. H. Hoffman to be sent out by the
Department of Mines, Manufac-
lures and Agriculture. Phosphor-
Gus, nitrogen and potassium, he
says, are the three plant-produc-
ing elements most necessary in soil,
and the supply of which most often
needs to be replenished. Lime, he
says, also is sometimes removed
from the soil in too great degree
by continuous cropping.
When crops are grown which are
taken from the farm the natural
result is a gradual decrease in the
fertility of the soil, according to
DR.. Hoffman, while on farms where
forage crops are grown and fed to
live stock, a great deal of the plant
producing elements are returned to
the soil through the farmyard ma
nure, if it is properly collected and
preserved. Where it is necessary,
through the continuous growing Of
such crops as cotton, to return to
the soil those plant-producing ele-
ments taken from the soil, it is Of
ten necessary, says DR.. Hoffman, to
supplement domestic manures
with a commercial product. When
this is necessary, he says, careful
attention should be given to the
needs of the given crop or soil, in
order to determine mors exactly
just what elements should be added
to the soil and in what proportion.
The tobacco plant" he says,
will require large successive appli-
cations of potash to produce sat-
isfactory crop, while cotton may be
grown for a number of years on
the same soil without the addition
of potash from external sources.
The cereals require liberal supplies
of nitrogen in the soil for their full
growth and development, while the
leguminous crops, by reason of
their capacity for assimilation of
nitrogen from the air, can be sue
cessfully grown upon soils quite
poor in nitrogen, and from which
nitrogenous fertilizers are with
held.
Most of our soils that have BEEN
in cultivation are lacking in great
err or less degree in all three of the
fertilizing constitutions, nitrogen,
phosphoric acid and potash, and
hence the very general demand for
complete fertilizers, supplying all
the above forms of plant food. Ex-
perience has shown that it is often
very advantageous to apply all
three of the fertilizing ingredients,
even where analysis of the soils
show quite appreciable proper
tions of these substances to be
present, since soil analysis only
show the total amount of the sew
eral constituents, and do not indi-
cate what proportion of these
is available to the
plant.
"On account of this difference in
value between available and I'M
available forms Of fertilizing con-
stituents, it is desirable to ascer-
tain not only the proportions Of
these constituents occurring in
commercial fertilizers, but the
forms in which they exist. The
manner in which the results of the
analysis is stated will enable the
purchaser to form an idea as to
the relative fertilizing value of
of different brands, for the
reason that not only is the total
amount of phosphoric acid given,
but also the relative proportions of
the three different forms of this
are set forth in the GER
tiiieate Of analysis. The potash re-
ported in the analysis is that which
is soluble or readily available to
the plant, while the nitrogen per-
centages represent the proportions
of total nitrogen found, though un-
der ordinary conditions the forms
in which this element is supplied
are quite available to the require
ments of the various crops.
The letter also states that plant
food may be made available for the
use of the plants to a much greater
degree than otherwise by the appli-
cation of improved methods of till
age, drainage, etc.