Oxford Democrat. [volume] (Paris, Me.) 1833-1933, 1913-01-28
Germ Life In the Soil.

Many people suppose that the soil is
simply mixture of fine rock particles
and dead leaves or other parts of plants
a place to be penetrated by the roots OF
the living plants, the roots absorbing so.
lutions of various chemical compounds
in order to grow.
Such a conception of fertile soil Ii
wholly inadequate. No one yet under
stands all the marvellous processes that
are going on in every cultivated field,
but enough has been discovered 10 show
that the soil is vast laboratory in which
untold billions of living things are work.
ing to bring about the possibility oil
plant growth. Ii is also place Of keen
est competition in which the organisms
are fighting one another for chance to
live.
The plant and animal materials added
TO the soil are not in condition to be
used directly as the raw materials OF
plant food. The carbohydrates, proteinS
and other highly organized materials, of
which dead animals and plants are COM
posed, must be reduced to simpler con-
ditions before they can again enter the
cycle of life. So they are attacked by
the uumberless bacteria that cause decay
or putrefactiou, and the complex COM
pounds are rapidly resolved into simpler
combinations. To large extent the car
bon and oxygen which were taken from
the air by the green plant cells are re-
stored to il in the form of carbon dioxide.
Much of the nitrogen and some of the by
drogen locked up by the growing plants
is set free in the form of ammonia gas,
part of which escapes into the air and
part of which at once unites with other
substances to form various chemical
salts, especially nitrites.
But the nitrites, which have been a
chief result of the work of decay induc-
ing bacteria, are not in condition to be
utilized directly by the green plants
They must be changed to another form
by combining with more oxygen. Here
also another group Of soil bacteria
comes into action. These change the
nitrites into uitrates, and they are
called the nitrifying bacteria. The nj
,rates are soluble in soil water, and so
are taken in by plant roots to use as the
raw materials ofgrowth.
Another important relation OF these
bacteria to soil fertility lies in the fact
that some groups of them are able to
take in the free nitrogen OF the AIR and
render it available for the raw material
of plant food. The air is q vast reservoir
of free nitrogen, but for the most part 1t
is useless to green plants directly be-
cause they do not absorb II Tor food.
This fact of the building up OF nitrogen
compounds directly from the air by Ger
tain soil bacteria is q recent discovery
which promises 10 be of great value In
explaining the nitrogen of the soil.
The beneficial relations of these soil
bacteria is by no means confined 10 nj
trogen compounds. Recent studies have
shown almost as important connections
between soil bacteria and phosphates,
sulphstes, potash and other raw mate
rials for plant food. The subject is COM
plex and difficult to investigate, but the
evidence grows stronger every year that
the supply of plant food in the soil de-
peuds chiefly upon the activities OF these
tiny germs whose very presence is un-
dreamed of by many farmers. The va
rious soil bacteria are not without enc
mics. Under certain conditions low
forms of life, somewhat like the slime
moulds, develop in the soil and kill on
the bacteria. Such soil soon becomes
less productive. This is also recent
discovery.
Tue practical lesson from all this study
of the bacteria in the soil Is that 1t Ia
we'll worth while TO treat the land 80
that these germs will be free to develop
under as favorable conditions as possible.
They live in dead plant or animal forms
or excretions, so these must be furnish.
cd. They require oxygen, so the soil
must be drained and tilled.-Clar ence
NJ. Weed in Tribune Farmer.