The progressive farmer. [volume] (Winston, N.C.) 1886-1904, 1898-07-12
.17TED BY BENZ IRBY, RALEIaH, n @
SOIL AUMUa.

.ariculturaI writer's. Mr. Bryan Ty-
am has recently had something to say
oft in these columns. A recent bulle-
tin of the North Dakota Station, dis
cnssing this important subject, opens
with the following statement:
ssTne matter Of humus in the soil is
attracting the attention Of all thought
ful farmers, aud many are asking for
information and how to prevent its
loss or how TO increase soil humus. An
attempt will here be made TO explain
Whist is meant by the term soil hunus
and in what way its presence IN the
soil is beneficial. Our statements are
based in part upon our own investiga'
tions and in part upon results drawn
from data of other stations" A few
definitions and explanations may IS.
sist in better understanding what may
follow.
That portion of earth that is cuiti-
vated for plant growth is the soil. 1t
is made up of mineral and organic mat
ter. The mineral matter consists OF
lime, potash, phosphates, iron, mag
nesia, aluminium and various other
minerals of less Importance.
The organic matter includes every
thing that onc9 existed as vegetable or
animal matter.
Volatile matter consists of the moist
ture gases and organic matter, al of
which can be driven eff from spade
full Of soil by heating it or burning it.
Humus is that part Of the organic
matter in the soil which has partially
decayed, such as leaf mold, rotten
roots and blades Of grass, clover or
peas. Rotted manure is rich In humus
Unrotted manure, or green crops
p!owed in, soon make humus by rot
ting down in the soil.
The opinion seems 60 be gaining
ground that much Of the available
plant food is the portion in the humus,
and as the humus increases In the soil
the potassium, phosphoric acid and
other mineral products existing in the
soil in insoluble forms not suitable for
! plant food are taken up by the humus
to form new compounds better suited
) to nourish the growing plants.
In eight determinations of North Da-
kota soils. Al per cent. of the phos-
pilates was found in the humus, and
the proportions ranged from 10 per
cent. to 81. OF the nitrogen from 46
to 80 per cent of the total was found
in the humus and on an average 81
per cent
What becomes of this nitrogen when
the humus is destroyed by decays It
goes back into the atmosphere or is
washed into the rivers and so carried
out to the ocean. In these ways five
pounds of nitrogen are lost for every
pound used by the growing crops.
II, then, the mineral matter taken
up by the plants and the nitrogen, are
drawn largely from the humus of the
soil, it will be seen how important It is
to maintain well the supply of organic
matter In the soil, that it may be trans.
formed into humus as needed by the
plants under cultivation. Continuous
wheat growing is a process destructive
OF humus and Of all organic matter in
the soil. Not that the wheat uses up
such large quantities, but under con.
ditions Of wheat growing as generally
practiced in this State, there is a rapid
decay Of organic matter, nitriication
under these conditions being very
rapid and the products escape as gases
into the air and are washed out of the
soil, or in case Of the mineral products,
phosphates, etc, they con. .bine in such
forms as to be no longer readily avail
able for feeding the plant.
An acre of soil to the depth of one
loot weighs about .225, 900 pounds, or
900 tons, and some soils as much as
1900 tons per acre. Experiments have
shown that soils containing the most
humus hold the most moisture, are
warmer, looser, mellower, most easily
worked and most fertile.
Following is summary of this i'm
portant bulletin on soil humus:
1. By twenty years of wheat grow
Ing from 40 to 60 per cent. Of the or
ganic matter of our soils have been
lost.
Z For every pound of organic mat
Ter that has gone to furnish its nitrogen
70 wheat, five pounds have bsen lost.
g. Many Of our soils that originally
contained from 5000 to 10000 pounds