Oxford Democrat. [volume] (Paris, Me.) 1833-1933, 1917-05-01
Natures Fertilizer Supply.
STANLEY B. Sink, Instructor in Agronomy, Soils
Division, at Farmers Week.


Division, at Farmers Week.
The most efficient means of using ma.
ture's store Of plant food would most
certainly be the key to permanent soil
fertility. Many have been the theories
by which this may be done. Among the
prominent theories that have been dis.
carded for newer ones are the water
theory, where the water was thought to
be the only source of plant food; the fine
earth theory where It was thought that
the plant took its food In the form of
fine particles of soil and that the f1uer
the soil the larger would be the crop.
The humus theory which held that the
only plant food necessary to be added
for permanent fertility was from the ad-
dition of humus; and many other theo-
ries that 10 time have become history.
Now we think We have the key to perma,
nent fertility, but perhaps few yesrs
hence it also will be relegated to the
background for new and better one.
At present we think that II the organic
matter supply Of the soil Ia kept up,
minerals supplied as they become used,
and deep thorough tillage practiced. the
fertility could be kept up indefinitely.
Chemists tell us that there Ia approx.
mately 5000. 900 pounds of nitrogen in
the air over every acre of land and from
this We may conclude that economy in
farming depends upon the use of some
of this natural store. 1t may be pur-
chased In commercial fertilizer but sure
ly that would be an unnecessary ex-
pense when there Is so much close at
hand and by the growing of legumes We
are enabled to draw this nitrogen from
the air. The clovers get about 2-S of
their nitrogen from the air and one-third
from the soil, and about 2,3 of the nitro
gen of the plant is found in the tops, so
1t ia evident that If all the tops are taken
off of the land there will be no addition
of nitrogen. Some authorities claim
that the next crop would be benefited
to some extent from having q legume
just preceding It, but not the second.
From the results covering 75 years at
the Rothamsted Experiment Station in
England, 1t is clearly proven that unless
some OF the legume is turned down.
there is so little gain that even the yield
of the next succeeding crop will not be
maintained.
The addition of commercial nitrogen
without organic matter has not proven q
means of keeping up the yield over a
period of years, so that we have but one
choice, and that Ia to get the nitrogen
from the air by the aid of legumes and
then turn down sufficient organic mat
ter, either in the form of green or animal
manure. Clovers and alfalfa are more
Efficient nitrogen gatherers than peas
and beans.
With reference to the phosphorus and
potassium supply, good productive
soil will contain from 1000 TO 1900
pounds of the former and 10000 to
SO, 900 of the latter 10 the plowed surface
Of an acre. While this may or may not
be sufficiently available to produce max
imum crop yields, q large percentage of
II ia capable of being made available
With any system of farming, the phos-
phorus supply will be heavily drawn up
on, but BY adding some phosphoric acid
to the manure or making it the principal
Ingredient of purchased fertilizer and al
ways having sufficient actively decaying
organic matter to work upon the 1000 to
200 pounds already there, 1t could be
kept up with but comparatively small
expense.
The addition of lime to sour soil is
also a means of liberating phosphorus
from the iron and aluminium compounds,
making it available.
The liberation of potassium involves
the same principles as does the liberia
tion of phosphorus. In Maine soils po.
tassium is the more abundant, and for
many crops potassium has not been
found to be limiting factor.
Green msnuring will be found profit
able when the soil Is depleted of Its Or
ganic matter to such an extent that no
crops will produce satisfactory yield
and can be worked In without the sacri.
fee of the seasons crop. or where suf1-
cient manure is not produced to ade-
auately cover the titled areas.
Deep and thorough tillage is another
way to liberate the store Of plant food al
ready In the soil. In some cases, a 80
percent increase has been reported for
good tillage. In comparing different
methods of getting the ground ready for
the seed, the Missouri: Station reports
that by just spring-toothing the land
they obtained yield of corn of 300 bu.
per acre; plowing 1-2 inches deep, 47.6
6u., and blowing 8 inches deep, 400 bu.
per acre. For wheat (osts stubble) disk
ed they obtained a yield of 4.29 bu., and
for plowed land, 15.2 bu. per acre.
Frequent cultivation for hoed crops is
very much to be emphasized. Iowa Sta
ton reports that when corn was cultivat-
ell s times, 5 inches deep, 1t yielded GO
bu. per acre, but when cultivated 8 times,
2 IL inches deep It yielded 10 bu. per
acre.
1t is evident that In order to liberate
the maximum amount Of plant food from
the soil by tillage, frequent and shallow
cultivation are to be recommended. This
with the supplementing of animal ma
nures, or If not obtaiuable, green ma
nures with phosphate fertilizers and
possibly potash, surely would prove an
economical way of using "Nature's store
~ Dlont food ~