The Owosso times. (Owosso, Mich.) 1897-1926, 1905-03-03
4 Visit TO a Nearby King
dom.
By C. D. Smith. Of the Agricultural College.
CHAPTER TX.

By c. d. Smith. Of the Agricultural College.
CHAPTER TX.
Air is as necessary an ingredient of a
fertile soil as water. 1t is as necessary
to the seeds at the time of termination
and to plant roots afterwards as is
oxygen to the human lungs, to sustain
life. Breathing conveys oxygen to the
lungs, or carbon dioxide as it is called,
from the lungs. So air moves into the
soil to carry oxygen to the plant roots
and to the bacteria engaged in convert
ing the decaying organic matter into
humus and to remove the excess of
carbonic acid gas from the soil. The
trouble with an undrained soil is that
the water excludes the air necessary to
the very life of the roots. On the other
hand when the soil grains are coarse
and the soil texture open and porous,
there may be too much air present. In
that case the decomposition of the de-
caying organic matter will go on too
rapidly and no humus will be formed.
The water will also escape and the soil
readily dries out. In soils with fine
grains on the other hand there will be
tendency to too slow movement of
air, too little air present and that
saturated with carbonic acid gas which
is not conveyed as fast as it should be
to the outer air. In such cases the de-
cay of the organic matter is hindered
or stopped altogether and the plant
roots smother for want of oxygen.
The air in the soil is kept in motion
by several forces. In the first place,
during summer the surface of the earth
is heated during the day and cooled at
night. The air in the soil expands
when it is heated and some of it is
forced out. When, at night the soil
cools, the air contained in It'll contracts
and pulls fresh air in from without.
In this way mature changes the air
about the roots of plants, in this way
the soil may be said to breathe.
at frequent intervals. When the
barometer rises, it means that the air
is pressing heavier on the earth.
Naturally some air will be forced into
the soil. When the barometer falls it
means that the air pressure is less, and
air is forced out of the soil.
Again, whenever hard wind blows,
coming in gusts, 1T aids in moving the
air in the surface foot of soil at least
and finally every rain must carry fresh
air downward with the sinking water
and force out other air, causing
which must ventilate the
soil.
The farmer, consciously or uncon-
sciously ventilates the soil by blowing
and other acts of tillage. When he
plows he causes a complete change of
air in the upper layer of the SOIL At
once the processes of decay are set at
work with new Ivigor. Plant food is
set free by the bacteria interested in
that work and the aeration of the soil
results in the final preparation for the
plant roots of large amount of plant ]
food until that time securely locked up |
in insoluble forms. The airing of the |
soil is one of the important benefits
upon the soil by blowing.
80 also narrowing bare soil, on
which crust has formed, helps as |
well in admitting air and allowing the
soil to breathe as in stopping the loss of !
water by evaporation. Often an oat or |
barley field will crust over soon after |
the'seed is sown, by reason of hard |
shower. The grain will scarcely sprout |
because the air supply is interfered
with by the crust. The soil cannot /
breathe and the seed cannot terminate. |
piece of spring grain is
rolled after sowing. The surface may |
be a little too wet The roller breaks
Town the soil kernels and crust is
formed when the soil dries. This stops |
the breathing of the soil and the plants
lie.
Where the air is excluded by too |
much water, there remains. of course |
nothing to do but to underdrain and |
carry off the surplus. Air follows the
water and the proper
growth of the plant roots follows as
oxygen is supplied in quantities suf-
icient.