Atlanta semi-weekly journal. (Atlanta, Ga.) 1898-1920, 1919-04-18
AGRICULTURAL EDUCATION
BY DR. ANDREW NJ SOULE $50"

I limited in exact proportion to the
supply Of that element of plant food
! shat is most deficient regardless. Of
| the abundance of all others.
! The nitrogen confetti of the soil is
! dependent upon the content of organ
lie matter; for decaying vegetable
matter is the principal source of soil
nitrogen. Clearly then. the first step
in soil building must be that Of great
! ly increasing the present meager sup
! ply of nitrogen through large addi-
| tons of humus formin% org Alic mat
| ter. 1t would be q mistake to as
sumo that this deficiency of nitro
gen could be met solely by the use
of commercial fertilizers. for the val
ue Of fertilizers is largely dependent
upon the physical and mechanical
condition of thesoi l, which in turn is
! influenced more by the content of or
ganic matter than by any other fac
tor. This explains why the produc-
| tiveness of the soil cannot be main
| tanned solely by the use of mineral
| fertilizers. AS the organic matter
becomes exhausted, increasingly larg-
err amounts of fertilizers must be
used to maintain yields, and the mar
gin of profit becomes smaller until
finally the fertilizer may be used at
a net loss, which is, in fact, some
times the case.
The methods to be followed in
maintaining and increasing the organ
ic matter and nitrogen must neces-
sarily depend somewhat upon the
type of farming being practiced.
Where dairying and other live stock
farming have prominent place, the
manure from the herds will go a
long way toward maintaining the
humus content of the soil. But it
would hardly be sufficient. 1t should
be supplemented by winter cover
crops and other leguminous green
manure catch crops, such as cowpeas,
soy beans, velvet beans, etc. These
legumes will not only increase the
humus content, but afford the only
economical means of building up the
nitrogen supply. In ordinary farm
practice, where cotton and corn are
the chief crops, these green manure
tanning organic matter and nitrogen.
They should be extensively grown
in general farming to prevent the
soil from becoming impoverished and
unproductive from continued crop
ping.
The practice of burning corn and
cotton stalks and other crop residues
cannot be too strongly condemned.
Referring to the table of plant analy-
sis it is seen that practically two
thirds of the plant food required for
a crop of corn or cotton remains In
SldlhS,
dues are burned, all the nitrogen is
lost, and the phosphoric acid and
potash remain behind in a few I'M
evenly distributed ash heaps, and are
of little value to the succeeding crop
because of the uneven distribution
over the land. This means a net loss
of over twelve dollars worth of plant
food when the stalks, leaves, ETC.,
from a one-bale cotton crop. or
hundred-bushel corn crop are burned.
Perhaps the organic matter lost
would have been equally as valuable
to the land as the plant food contain
ed in the residues. The total loss,
then, when the farmer burns these
materials, is about $25. Probably no
other single factor has done so much
to cause the soils of the Piedmont
section to become run down or worn
OUT as this practice of burning off
all litter in the spring. Certainly the
loss suffered when these resldues
are burned makes it worth while to
go to the necessary expense and trou-
BILE to get them in condition for ploW-
ing under.
The function of nitrogen is to pro-
due growth in the plant itself Civ
ing size of stalk and limb, and deep
green color to the foliage. It's needs
can be readily detected by weak.
stunted plants and the absence OF
deep green color.
Phosphoric Acid---After nitrogen
and organic matter, the next constft-
uent which needs to be increased in
the average soil of the country is
phosphoric acid. There is a wide diff
ference, however, in the content Of
phosphoric acid in the different soils.
In general, the red soils are better
supplied with this constituent than
are the gray or yellow soils. This
is probably due to- the large amount
of iron in the red soils which holds
the phosphoric acid in an almost i'm
soluble combination. The presence
of fairly large amount is, there
fore, not an infallible indication that
phosphoric acid is not needed since
tent in a form that becomes avail
able with extreme sloWness. The
need for available phosphoric acid
has been generally recognized in the
use of fertilizers relatively high IN
this element, but the practice does
not generally take into account the
different soil types on which the fer
tlizer is to be used. The available
ity of the phosphoric acid is largely
dependent upon the content of. or
ganic matter and the general physic-
al condition. of the SOIL so that even
be Of little value when the land is
allowed to get in a rundown condi- |
ton from continued clean cultiVa- |
ton.
q. III lSIlllIASIS u9Su ulI cGtly uIQSl
crops to meet immediate needs, phos- |
phoric acid should be applied in the |
form of acid phosphate or other |
available form. However, in scheme
of permanent agriculture, where soil |
building is an object rock phosphate |
affords the cheapest source of phos- |
phorus. Phosphoric acid can be !
bought in this form for about one !
per cent per pound, whereas, it costs |
several times as much in the form of
acid phosphate. However, the soil |
must be we'll stocked with humus in
order to get good results from rock
phosphate; for 1t is only in the pres
ence of decaying organic matter that
this material will give up it's phos-
phorus. In connection with green
manures or with heavy applications
of farm manure, rock phosphate
should give good results. 1t should |
be applied broadcast at the rate of
1000 to 1000 pounds per acre about |
every five years. This should be sup
p1emented with small amounts of
acid phosphate, if needed, but the !
quired will be greatly reduced and a
net saving made. IT is we'll to re-
member, however, that rock phos-
phate, of whatever brand or source,
cannot take the place of acid phos- |
phate in mixed fertilizers and farm
ers should not buy it for this pur-
pose.
Phosphoric acid performs a special
function in the fruiting of plants
CATCH FISH
EELs, muskrats and other iur-bearing ami