American Falls press. [volume] (American Falls, Idaho) 1907-1937, 1909-02-20

building them up in still different ways
1t makes the hard wood of the oak or
the delicate petals of. a 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 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 a fire
or even breathes he is adding to the
store of this material in the air.
The smooth upper surface of a leaf
is both air and water tight. On the
undersfde, 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 chlorophylI.
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
oreathed out by animals. In this way
plants make animal life possible. Ami
mails give off carbon dioxide and
manure 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 1t 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 at
mospheric nitrogen into forms in
which the plant can use it, We shall
study more about this process later.
Nitrogen IS one of the -most impOr-
tant plant foods, and it Is one that is
very often lacking II the plant can
not get a sufficient supply of nitrogen
it viii be stunted. viii stop growing /
early. and the yield will be very much /
reduced. Since all the crops, with the (
exception of the legumes. must get 1
heir nitrogen from the soil, the farm /
Pr must see to it that there IS a plen- I
-iful supply there If he wishes to OBJ .
ain a large yield.
If you win drop a little rich black
soil ON a hot shovel some of it will
20 up in smoke. The part that buYns Is I
lumus and is made up of vegetable and
animal matter which is partly de,
cayed. This humus contains large
amounts of nitrogen, and from this