Atlanta semi-weekly journal. (Atlanta, Ga.) 1898-1920, 1918-04-23

more important than having the soil
well supplied with a sufficient amount
OF available plant food of an essential
character. \ study of the soils of
Georgia shows that most of them are
more or less deficient in those ele-
ments which We regard as essential to
the growth of large and profitable
crops. These elements. stated i'm the
order of their Importance, are probably
nitrogen. phosphoric acid. potash and
lime. Many other constituents enter
into the composition and development
.Of plants. but as a rule most or them
ARE found in the soil in sufficient
amount TO meet the requirements of
average field crops. Under existing
conditions. the supply of nitrogen is
somewhat limited by reason of our in
ability. through lack of ships, to obtain
our usual supplies OF nitrate of soda
from South America. The government
has also found il necessary to take
over the output of sulphate of am
mOnia for war purposes. Hence, farm
ers are more dependent than ever on
their own resources for securing and
Applying to the land the considerable
proportion of nitrogen needed by our
southern soils. Potash is available
only in limited quantities by reason of
war conditions.
There are two elements, however,
very essential to plant growth which
we can obtain still i'm almost unlimited
quantities. One of these is acid phos-
phate, a carrier of phosphoric acid, and
the other, calcium, derived from the
crushing and application to the soil
of finely powdered rock, which con-
sists primarily of calcium carbonate
and commonly called limestone. 1t is
true that acid phosphate is now higher
than in previous years. and that it is
not so plentiful, due to the fact that
large quantities of sulphuric acid are
required for war work. At the same
time. it is still relatively abundant
This being true. it is important to
ascertain just what it's relation 70 crop
production may be at this time and
how extensively it should be used in
agricultural practice under existing
conditions.
Phosphorus acid is known to be in
timately concerned with the production
OF grain and the fastening of the ma
turity of farm crops. 1t is very inn
portant that an element which confers
this advantage on plants be used rath-
err extensively. therefore, under all
crops, but particularly under grain and
must be brought to maturity in the
shortest possible season. Its use in
those sections of the state where the
boil weevil is likely to prove destruc-
tive is therefore very important. The
fact that it is markedly deficient in
our Georgia soils also enhances its
value in our agriculture. 1t is well
known that in many instances where
the land seems to produce a good-sized
plant, say of corn and cotton. that the
yield is found 10 be quite unsatisfac-
as.~w
phosphate be made. When this is done
il is surprising to find the improve
menU in the yield of grain and the out
turn of cotton which follows. There
fore, we must regard this element as
one of the most important and essen
tial TO our agriculture, and hence, il is
wise and proper that farmers should
make every effort to use II intelligently
and in sufficient amount to supply the
requisite quantity of this element to
the crop concerned.
Under ordinary field practice it is
best TO use from 200 to 500 pounds of
acid phosphate per acre. For field crops
zoo to 800 pounds will answer very
we'll and the same amount will be suf-
ficient for legumes. On soils which are
very sandy, and therefore more likely
TO be deficient in this element than 9TH
ers, 800 to 500 pounds per acre can oft
en- he made to advantage. This is espe-
cially true of many of our truck crops.
PhoSphoric acid is not an element which
is readily leached from the soil. There
fore, our experience indicates that il IS
best as a rule to put most or all of this
element under the crop or into the land
before planting is done. AS it is taken
up rather slowly il is an advantage to
put it in early so the crop may have
a.
assimilate and utilize it. Mixing il with
the soil insures its most thorough and
complete distribution, and therefore af-
fords the plant the best opportunity of
feeding upon il. For the reasons stated,
il is not good practice, as a rule, to use
acid phosphate as a side application.
However, if this is done, it should be
mixed with the soil and put on early
in the season of growth. To wait until
the crop is half matured and then use
it is therefore inadvisable.
AS to the form and kind of material
to apply to our soils, there has been
considerable argument and debate in
recent years. There are those who have
believed that acid phosphate was the
most desirable carrier of phosphoric
acid. Others have strongly advocated
the use of basic Stag. steamed bone or
the finely ground raw rock which carries
The equivalent of so per cent or more Ct
-.hoSphoric acid. The finely ground raw
~Ock does not contain this element in ?
readily available form, and such bene-
Icial fesults as have been obtained from
its use have come primarily from those
soils very rich in organic matter and
which are seldom met with in the south
When the raw ground phosphate rock
can be combined with yard manure in
compost good results are sometimes OBJ
tanned. Where one can afford to wait
for a long period Of time. it's use may
often prove advantageous. For field
conditions as they now pertain and for
quick results. however, il does not COM
pare favorably with acid phosphate &C
cording 10 the tests and observations we
As for basic Stag, il only contains about
half as much available phosphoric acid
as the acid phosphate of commerce.
Hence. il is a slow-acting material rela-
lively speaking, and not so desirable for
use under our conditions because of the
deficiency OF our land in organic mat
ter.
10 steamed bone is a desirable carrier O.
phosphoric acid for such crops as wheat
and other lOng-seasOn growing cereals.
II must he put on in considerable guam
titles and patience exercised before re-
suits are obtained, because the bone IN
measure must decay before the phos
phoric acid it carries becomes available.
While we would advise the use Of
steamed bone under certain conditions.