Eagle River review. [volume] (Eagle River, Wis.) 1890-1927, 1925-11-12
Green Manuring
Improves Soil
Crop Turned Under Contrib
utes Fertilizing Elements
Needed.
prepared by the United States Department
of Agriculture.)

prepared by the United States Department
of Agriculture.)
Green manuring as a means of in
creasing or maintaining soil produc-
tfvity has come down to us from an
Gent times. The agricultural frater-
nifty early discovered the value of
turning under crops while green or
soon after ripening for the purpose
of soil enrichment. Nitrogen, very
costly element when purchased in con
centrated form, exists N unlimited
quantity in the atmosphere. When a
green-manure crop is turned under it
contributes to the soil not only the
various fertilizing elements that have
entered into the production of the crop
itself, but it also adds to the soil a
quantity of organic material thereto
fore not present. This organic mat
ter, or humus, is beneficial in a num-
Der of ways. 1t makes the soil more
porous and therefore capable of alb
sorbing large amount of water. This
increased supply Of humus is especial
ly desirable in the case of heavy clays
and sandy soils.
Requirements of Roots.
The roots of most crop plants need
a moderate amount of air and mois-
ture. They are thus enabled better to
withstand drought and to produce
greater yields. Soils rich in humus
admit air more readily and retain
larger quantities of water Like the
camel on transdesert Journey, such
soils often imbibe sufficient water to
last until the next oasis or drought
breaking rain is reached. 1t has been
shown that while 100 pounds of sand
can hold only % pounds Of water and
100 pounds of clay so pounds, the
same weight Of humus or decaying or
ganic matter will hold 100 pounds.
This is a most convincing argument
that the farmer should SO increase
the instrumentation capacity of his
soil as to provide reservoirs of water
against the time of drought.
AS the green manure, after it is
turned under, decays, it provides food
for soil bacteria. These bacteria break
down and make available for use by
crop plants the organic matter con-
tanned in the SOIL
The roots of legumes, the most de-
sirable of crops for green manuring
purposes, have on them growths of
varying sizes known as nodules. These
nodules are produced by bacteria, the
latter drawing their sustenance from
the host plant, the legume. These
bacteria, however, in the beneficial
work they do, more than earn their
board. The nOdules serve as la0ora-
tories for the bacteria, whose task is
to bring down into the soil for plant
use supply of free nitrogen. When
these legumes are turned under the
nitrogen, after passing through certain
chemical processes, is changed into
nitrates, food as popular with crop
plants as baked beans with Boston
Yankees.
The question as to whether the en-
tire crop Of legumes should be turned
under or the hay cut and merely the
stubble plowed under is one to be de-
termined largely by the degree of soil
fertility and porosity, the system of
agriculture followed, and other local
conditions. In general, however,
where the need for soil Improvement
is urgent, the entire crop can, with
greater profit, be turned under.