Pullman herald. [volume] (Pullman, W.T. [Wash.]) 1888-1989, 1912-06-28
SOIL HUMUS

For many years the soils of Wash.
ington have been cultivated, but dur
ing this time probably not great
many farmers have given any special
attention to the conservation of the
al 5 fertility.
Experiments carried on in the
washington Experiment Station have
shown that the soils of the dry-farm-
ing districts of the state are rapidly
being deprived of their humus and
nitrogen. A loss of humus affects
the soil injuriously in three ways:
First, by reduction in the amount
of nitrogen, one of the very import
ant elements of fertility; second. by
causing the soil to be much harder to
work, and third, by reducing the
water holding capacity, which is, in
our dry lands, an absolute necessity.
Our methods of summer tillage are
largely responsible for the great
losses from the soil, for, when the
organic matter is exposed to the sun
and given free access to the air
through frequent cultivation, it Is in
the most favorable condition for the
process of oxidation. BY this oxida-
ton process the humus is converted
into gases which pass into the air,
and thus become lost to the soil
During the fallow year no vegetable
matter is grown and consequently no
humus is given to the soil.
Since the loss of humus results in
a loss of nitrogen, water holding
capacity, and friability, it is quite
evident that the improvement of the
humus supply is of very great inn
portance in the maintenance of the
fertility of our dry farming lands.
Suggestions for changes in the
present system are best given in the
following extract from the Sixth In
ternational Dry Farming Congress of
the committee on the maintenance of
fertility of the soil under strictly dry
farming conditions.
THE humus supply of the soil
may be increased by regularly plow-
ing under all the stubble and straw
which is grown on the land, supple
mented by any green cover crop
which conditions VIII permit to grow
during the late fall or early spring
months. All such material should be
plowed under as soon as possible
and should preferably be chopped up
and mixed with the soil by thorough
disking before blowing. Treated in
this way, it can be put into the
ground in good shape to decay and
with the least possible danger of
causing the soil to dry out so that the
following crop will burn out. 3"
Crops grown on lands which have
their humus supply deep in the soil
will naturally develop deep roofing
systems and will be better able to
'A|HS'ttAiN VI Cu5hL anu " VI IL w
larger supplies of plant food.
THE leguminous crops are the
greatest known soil renoyators and
the best and cheapest source of hui
mus and nitrogen for green manur-
ing purposes. But, unfortunately,
over much of our western country
the conditions which make dry farm
ing methods of cultivation necessary,
also makes it nard to grow the le-
guminous crops successfully or
profitably. One of the important
fields of investigation in dry farm
ing is therefore the ascertaining Of
methods by which legumes may be
grown to be plowed under for the
purpose of increasing the supply of
those constituents In which dry
land soils are most seriously def
cient.
alfalfa is at present the only le-
gume which appears to have any
very general applicability to dry
farming conditions. But alfalfa is
not well adapted to short rotation
systems. To grow this crop profit
ably and to derive the most benefit
from 1t to the soil, it must stand for
several years before being ploWed
under and must be at its maximum
growth when turned under This
necessarily means a long rotation
system, and one which must be care
fully worked out in each individual
locality in order to properly utilize
all the available land each season
and to insure a proper balance of
crops produced.
"On dry farming lands whose
chief characteristic is deficiency in
humus and nitrogen, farm manure
is of exceptionally high value as a
coil raDovotor Etvarv available ton