Oxford Democrat. [volume] (Paris, Me.) 1833-1933, 1909-08-03
The Action of Manures.

The Action of Manures.
After over hundred years of system.
attic use there still remain differences OF
opinion as to the action of manures IN
promoting plant growth. The value oi
the decomposed or rotted vegetable mat
ter often called humus, has been given
first place in many text books on farming,
vet the usefulness of humus as such has
failed of direct proof. In Southern New
Jersey, where the soil is frequently
almost pure sand and should show the
greatest need of any type of soil for
humus, most of the successful sweet
potato growers do not use barnyard
manures at all, but rely wholly upon
chemical fertilizers.
A similar illustration is found In the
world-famed experiments in manuring at
the Rothamstead experiment farms in
England. These experiments include Q
series of tests with farmyard manure and
chemical fertilizers, side by side. The
soil in both tests is the same and the cul-
tural treatment is the same. The farm
yard manure is used literally and is we'll
prepared manure at that; yet for more
than sixty years of wheat on the same
soil year after year, the chemical fertil-
izer uniformly gives the better returns,
there can be no shadow of question upon
these experiments. They are conducted
continually under the most exacting and
competent supervision.
Now as to the value Of humus in
improving the physical condition OF q
soil. 1t is sure that few crops leave as
little vegetable matter in the soil as do
wheat and sweet potatoes. Yet the fact
remains that with little or no humus the
chemical fertilizer had proved more
effective than farmyard manure.
There can be no question as to the fact
that farmyard manures are valuable.
The question, If any question exists at
all, is as to the action of this manure.
As shown by the above instances, the
humus theory has little or no value as
such. But humus in the common under
standing of the word, means simply rot
ted manure, that is, bulky farmyard and
stable refuse rotted down, concentrated,
until perhaps eight or ten tons of this
roughage is rotted down to one ton.
This one ton will contain pretty much all
the nitrogen, potash aad phosphoric acid
originally contained in the eight or ten
tons of roughage, and it seems more than
likely that it's beneficial action is due to
this nitrogen, potash and phosphate,
that is, its value increases as it approach
es more nearly the composition OF the
chemical fertilizers.
1t is surely probable that humic mat
ter may have an agricultural value be-
yond its mineral contents, in the shape
of conserving soil moisture, or prevent
ing the free teaching away by rains, ETC.,
of the valuable mineral contents. This
is an action which must be given due
credit, and must be understood as to its
proper utilization. For quickly grow
ing crop, such as small fruit, vegetables,
spring wheat, etc., the ready availability
of the plant food is vitality important,
but for grass, or even corn, a manure OF
slower action may be used. The pre-
sumption is, that humus holds its nitro
gen, potash and phosphates in an insolu-
Bile form, and so long as these materials
remain insoluble they are not effective
as plant food. By keeping the soil brok-
en-, air and sunlight have a more ready
access to its particles and the action OF
these agents is to decompose organic mat
ter. The humus is broken up, and in
doing so, the nitrogen, potash and phos-
pilates are freed and become soluble.
Therefore, farmyard mauures should
be used with crops of clean cultivation,
such as corn. 1t would seem that wheth-
er farmyard manure or fertilizers are
used, what is chiefly wanted is nitrogen,
potash and phosphatss. 1t is as we'll to
state here that all three elements are
needed, and that no one, nor any two OF
them supplied in excess, can make good
the shortage of any one of them. This
means that the gauge of the crop is that
of the plant food element most deficient
and least in quantity.
There are differences OF opinion as 10
the proper proportions of the plant food
elem ents for various crops. As shown
by examinations of complete crops OF
various kinds, it would seem that all
three Ingredients are needed in about the
same proportions. Soluble phosphates,
however, are likely to become more or
less insoluble in the soil, and to allow for
such action, they are usually added some
what in excess of the indicated actual
needs. Nitrogen is stored in the soil by
the action of the various bacteria, anc
this element may be given in what woulo
seem deficient quantity. Potash, as a
chemical fertilizer, is always readily
available and should be supplied about as
needed, as shown by the amount removed
by the crop.-R. Garwood.