The morning news. [volume] (Savannah, Ga.) 1887-1900, 1894-05-21

ANs
plemented by cheap fertilizers. In three
years marked improvement was evident,
not only In the physical character of the
SOIL, but also in the increased yields of
various crops
Again, green manuring may be used to
take the place of more expensive fertil-
lzers and manUres on soils already under
cultivation. 1t is in this latter use that
1t finds its widest application
There has been much speculation as to
the manner IN which the crops commonly
USED for green manuring could gather
such large quantities of fertiliziug
materials. 1t will be remembered that
the principal fertilizing ingredients re-
CURED by plants are nitrogen, phosphoric
acld and potash. These are eacn and all
more or less essential to the healthy
growth of crops. Consequently, they are
appIled to the soil in the form of CONNER
clal fertilizers and other manures In at
tempting TO explain how the fertility of
the soil IS maintained by green manuring
1t has been said that plants with long
roots, like Covers, feed deep down in the
soil or subsoll on materials beyond the
reach OF surface feeding plants; and that
when the tops of these plants die down
and are mixed with the surface soil they
enrich it much the same as an applica-
tlon of barnYard manure. This is I'M
doubtedly true, but it fails to
explain how such large quantities of ma
terlals can be obtained, especially when
clover is grown continuously for num-
Der of years. The question has finally
been solved by one of the most interest
ing and Important discoveries vet made
in agricultural science 1t has been found
That certain plants can feed upon the
nitrogen 10 the atmosphere, and store it
up IN their tissues as they grow They
take their phosphoric acid and potash
from the soil, but they obtain their nitro
gen very largely from the air. Hence
they draw from the air a material neces-
sary to the growth of crops, which in the
form of commercial fertilizers, as nitrate
OF soda, ammonium sulphate, dried blood,
etc, is paid for at the rate of from 10 to
20 cents a POUND
HOW PLANTS GET NITROGEN FROM THE AIR.
The air we breathe is about four-fifths
nitrogen and one-hfth oxygen. We use
the oxygen in breathing but discard the
nitrogen. 1t has been REGARDED merely as
material for diluting the oxygen, which
would otherwise be too strong for our use
All attempts to economically render this
nitrogen of the air available for plant
1000. by chemical means, have been I'M
successful. Recently it has been discov-
cred that the so called leguminous plants
-clovers, peas, beans, lupines, vetches,
etc. can take up this nitrogen of the air,
and can grow without being MANFRED
with nitrogen if MANFRED with phosphoric
acid and potash.
The manner in which this nitrogen as
similation takes place has been carefully
and patiently studied by scientists, and
although the details are not fully under
stood, the primary cause has been found.
IL is believed that plants are enabled to
get this nitrogen through the activity of
the lower forms of life, bacteria or
microbes, which can only be seen with the
aid of powerful microscope. These or
ganlsms live in the soil, and are to be
found where leguminous plants have been
grown. They produce or cause the plant
to produce little nodules, or tubercles, on
the roots. 1t is through these tubercles
that the plant gets its atmospheric nitro
gen. The air enters the soil by the num-
erouS pores or openings in it, which
are produced by blowing, cultivating
and working the soil, by the decay of
rootleSs, by earthwOrms, etc. By just
what physiological processes the nitrogen
assimilation takes place is question still
In dispute among scientists. 1t is sufficient
for practical purposes to know that nitro
gen is taken up from the air by the grow
ing plant, directly or indirectly; and that
this nitrogen assimilation takes place as a
result of the life of bacteria 1t is Pc
culiar fact that few, if any, root tuber-
Giles are formed when leguminous plants
are manured with nitrogen; the plants
must first hunger for nitrogen before the
tubercles are formed and tne presence of
tubercles indicates that the plant TAX
ing nitrogen from the air.
Now, curious as it may seem. there APP
pear to be different forms of bac-
terra for different kinds of plants
Hence it sometimes becomes necessary to
provide crops with the necessary bac-
terra before they can use the nitrogen of
the air. This is done by applying light
dressing of soil in which the kind of
plants it is wished to grow have been pre-
viously grown. This is called soil inocu-
lation. IL is sonnet imes necessary in
growing crop on piece of land for the
first time in several years. Suppose, for
instance, that peas which had been sown
on land MANFRED with phosphates and
potash but without nitrogen failed TO
grow luXuriantly. If the other conditions
were favorable the inference would be
that bacteria of the right kind were lack
ing in the soil, and light dressing of
soil in which peas had previously been
successfully grown might be applied.
Such treatment as this has been re-
peatedly tried with success on large
scale.
These discoveries throw new light on
green manuring and on the plants best
adapted for green manurlng. They recon-
mend it more highly than ever before as
a soil renovator and a cheap means of
maintaining the fertility of soil. They
show that while leguminous and nom
leguminous plants enrich the soil alike in
humous-forming materials, in proportion
to the size of the crop, they differ in re-
spect to the source of their heterogeneous
materials. While non-leguminous plants
derive their nitrogen supply almost ex-
clusively from the soil. leguminous plants
may take theirs largely from the air. Con-
sequently, if spurry, buckwheat, mustard,
etc. (non-leguminous plants, are grown
on the soil and the crop plowed in, the
soil is not materially enriched in nitro
gen; the process is simply returning to
the soil all the nitrogen which the crop
took from it. But since leguminous plants
may derive the larger proportion of their
nitrogen. from without the soil-that is,
from the air-their use for green manur-
ing actually enriches the soil in nitro
genous matter
1t will thus be seen that by green ma
nuring with leguminous crops it is posi-
bic to manure the soil with nitrogen from
tho al F.aa ord ipavb a7etibla conrna