The Ohio Democrat. (Logan, O. [Ohio]) 1886-1906, 1894-06-23
LeouM,Nous PLANTS.
How They Take Up Nitrogen and EnricH
the Soil for Crops.

How They Take Up Nitrogen and Enrich
the Soil for Crops.
A recent bulletin issued by the de-
partmcnt Of agriculture contains inn
portant information on the value and
use of lcguminous plants for green
nanuring and for feeding. A chapter
If the bulletin entitled GLOW Plants
Get Nitrogen from the Air" is especi-
ally valuable. and is in part as follows:
"Thc mir we breathe Is about four
ifths nitrogen and one-fifth oxygen.
We use oxygen in breathing, but dis
card the nitrogen. 1t has been regarded
merely as a material for diluting the
oxygen. which would otherwise be too
strong for our use. All attemps econ
omically to render this nitrogen avail
able for plant food by chemical means
have been unsuccessful. Recently II
has been discovered that the so-called
leguminous plants-clover, peas. beans,
lupines, vetches, ctc.-can take up this
nitrogen of the air, and can grow with.
out being manured with nitrogen u
manurod with phosphoric acid and
potash. The manner in which this nj.
trogen assimilation takes place has
been carefully and patiently studied BY
scientists, and although the details are
not fully understood the primary cause
has been found 1t is believed that
plants are enabled to get this nitrogen
through the activity Of the lower forms
of life, bacteria or microbes. These
organizations live in the soil and are tc
be found where leguminous plants have
been grown. They produce, or cause
the plant to produce, little nodules, o,
tubercles on the roots. tits through thess
tubercles that the plant gets its atmos
pheric nitrogen. BY just what phys
iological process the nitrogen assiinila
tion takes place is question still in
peculiar fact that few, if any root
tubercles are formed when leguminou,
plants are manured with nitrogen; the
plants must first hunger for nitrogen
before the tubercles are formed, and
the presence of tubercles indicates that
the plant is taking nitrogen from the
air.
''Now, curious as it may seem, there
appear to be different forms of bacteris
for different kinds Of plants. Hence il
sometimes becomes necessary to pro
vide crops with the necessary bacteris
before they can use the nitrogen of the
air. This is done by applying light
dressing of soil in which the kind o.
plants it is wished to grow have beer
previously grown. This is called sol,
incubation. 1t is sometimes necessary
in growing a crop on piece Of land fol
the first time in several years. Suppose
for instance. that peas which had been
sown on land manured with phosphates
and potash, but without. nitrogen
failed to grow luXuriantly. If the
other conditions were favorable the in
ference would be that bacteria of the
right kind were lacking in the soil and
a light dressing of soil in which pea.
had previously been successfully growr
might be applied. Such treatment a,
this has repeatedly been tried with sue
cess on u large scale. These discoverie,
throw new light on green manurine
and on plants best adapted for green
manuring. They recommend it more
highly than ever before as Il a soil rem
ovator and a cheap means of maintain.
ing the fertility of soil. They show
that while both leguminous and non.
leguminous plants enrich the soil alike
in humus-forning materials, in proper.
tion to the size of the crop. they differ
in respect to the source of their nitro
genous materials. While non-legumin
Gus plants derive their nitrogen supply
almost exclusively from the soil, legum
inous plants may take theirs largely
from the air. Consequently if spurry
buclkwheat, mustard, etc. (non-legumin
Gus plants), are grown on the soil anG
the crop plowed in the soil is not ma
terially enriched in nitrogen, the pro
cess is simply returning to the soil al
the nitrogen which the crop took from
it. But since leguminous plants may
derive the larger proportion of theil
nitrogen from without the soil; that is
from the air, their use for green ma
n,lring actually enriches the soil in nj
trogenous matter. 80
''It will thus be seen that by greer
manuring with leguminous crops it il
possible to manure the soil with nitro
gen from the air, free and inexhaust
ible source, and thus avoid buying fer
tiliAers' containing much nitrogen
This greatly lessons the expense fol
commercial fertilizers, for nitrogen il
the most expensive element the farmer
has to buy. 1t costs from fifteen tt
twenty cents a pound, while potasl
and phosphoric acid cost only five tt
seven cents, or even less. Although
grains. grasses, corn, cotton, root crops
tobacco, etc, cannot use the nitrogen
OF the air, green manuring enable!
them to benefit by it indirectly.-Chi
cago Tribune.