Yorkville enquirer. [volume] (Yorkville, S.C.) 1855-2006, 1909-02-12
FIG. 111-THE GROWTH OF CORN ROOTS.

building them UP in still different ways
it makes the hard wood Of the oak or
the delicate petals Of rose. Man,
with all his skill and machinery, has
never been able to make any products
half so wonderful as are being made
every day in every field on your farm.
If plants are to grow rapidly and
produce large yields, they must be well
fed. About half the dry weight Of a
| mature plant Is made up Of carbon.
Practically all Of this comes from the
carbon dioxide of the air. Every acre
of wheat will use ton Of this gas or
all that Is in a layer Of air three miles
deep over the acre. The constant mix
ing of the air by the wind is always
bringing fresh supplies within reach
Of the plant.
The farmer does not need to concern
himself with the supply Of carbon di-
oxide, for every time he builds fire
or even -breathes he is adding to the
store Of this material in the air.
The smooth upper surface Of leaf
is both air and water tight. On the
underside, however, are many small
openings, which are really the mouths
of the plant. 1t Is through these tiny
holes that carbon dioxide is taken into
the leaf to be used by the chlorophyll.
In making starch and other products
out of carbon dioxide and water some
oxygen Is given off. This passes out
| through the openings In the leaves.
Thus you see that plants breathe In
much the same way as animals do,
only they give off oxygen, the product
which is used by animals, and take up
carbon dioxide, the gas which Is
breathed out by animals. In this way
plants make animal life possible. Ami
mails give off carbon dioxide and man.
ure as waste products. Plants tear
these waste products to pieces and by
rebuilding them make them once more
into food for the animals.
Next to carbon, hydrogen and oxy-
gen are the foods that the plant uses
in largest quantities. Since water Is
composed of these elements, the sup
ply will be plentiful as long as there
is plenty of water in the soil.
There is one element, nitrogen,
which forms a considerable part of the
plant, that is harder to get. While
three-fourths of the air is nitrogen, the
plant does not seem to be able to use
II in this FORM The only kind Of plants
that can use the nitrogen in the air at
all are the legumes, such as clover and
alfalfa Certain bacteria that live on
the roots of these legumes have the
power of changing the atmospheric nj
trogen into forms in which the plant
can use it. We shall study more about
this process later.
Nitrogen is one Of the most fmpor-
tant plant foods, and it is one that Is
very often lacking. If the plant cannot
get a sufficient supply Of nitrogen 1t
will be stunted, will stop growing ear
ly, and the yield will be very much re-
duced Since all the crops, with the
exception of the legumes, must get
their nitrogen from the soil, the farm
er must see to it that there Is a plenti-
full supply there If he wishes to obtain
a large yield.
If you will drop a little rich black
soil on a hot shovel some Of 1t Will
go I'D in smoke. The part that burns
Is humus and Is made up Of vegetable
and animal matter which Is partly de-
cayed. This humus contains large
amounts Of nitrogen, and from this
source the greater share Of this ele-
ment used by the plant must come IL
your soil is black, spongy and well
supplied with humus there Is little
danger that the plant will go hungry
for nitrogen. One of the best ways to
keep a field in this condition Is to ap-
ply liberal quantities Of barnyard ma
nure. Another way Is to plow under
green crops, especially clover. Some
times it is necessary to buy nitrogen
for the plant in the form Of commercial
fertilizers, but this is very expen-
sive way of obtaining it.
Even when the plant is given all the
nitrogen it can use it sometimes rails
to do we'll. This is because 1t cannot
get as much Of the mineral elements
as it needs.
Too much nitrogen in proportion TO
the amount of mineral elements causes
the plant to "go all to vines" There
will be an excessive growth of leaves
but the yield Of grain will be small
Take an ear Of corn or bunch OF hay
and burn it. The ashes that are left
are the mineral parts OF the plant.
These cannot be obtained from air OF
water, but must come from the SOIL.
Some of the most important of these
are iron, which is the substance that
helps to build up chlorophyll, and sui
phur, which is found in the nitroge-
nous parts Of the plant. There are
number of others also, all Of which