The farmer and mechanic. [volume] (Raleigh, N.C.) 1877-1885, 1878-06-20

not we'll understood, a further con-
siderable amount of nitrogen derl-
we'd from the atmosphere, either 10y
the growing crops. or by the soil
itself. 1t was long ago observed by
Boussingault, that the nitrogen
contained in the crops moderately
MANFRED does, in the long rur, y
ceed the nitrogen supplied IN the
manure, and to ii greater extent
than can be accounted for by the
agency of rain. The field expert
ments at Roth: instead can afford
the best evidence on this point.
Wheat and barley crops grown year
after year on the same land, ma
nured with phosphates, potash, and
other ash constituents, but receiy-
ing no nitrogen, have yielded on an
average, eighteen to twenty-five
pounds Of nitrogen annually Is
corn and straw, during twenty
four years. These crops are, how
ever, slowly falling off; it is posi-
bic, therefore, that "a part of the
nitrogen has been obtained from
former accumulations in the soil
Beans grown with purely cinereal
manure have yielded in twenty
one crops an average OF forty-tive
pounds of nitrogen per annum this
crop. too. has fallen off. The
strongest evidence of assimilation
of nitrogen from the atmosphere
is. however, to be found in the eX-
periments with meadow land, and
with a rotation. With meadow
land manured with purely cinereal
manures, the average nitrogen IN
the produce during twenty years
has reached the large amount of
fift-five pounds. On this plot there
is, at present, no sign Of falling off
in the produce. The cinereal ma
nure has developed a large amount
of clover, and this is doubtless one
reason of the heterogeneous character
Of the crop. On the rotation field,
whether we take the entirely IN
MANFRED rotation, or the rotation
receiving superphosphate only, or
that which is literally MANFRED
both with nitrogen and ash consti-
tuents, we find in each case that
the annual yield of nitrogen by the
crops during tw~enty-eight years Is
more than t~hirty-six pounds in ex-
cess of hat supplied as manure. In
the case of the literally MANFRED
rotation, a falling off in the cropsis
hardly to be expected.
A part of the atmospheric nitro
gen thus assimilated is doubtless
taken up by the crop as gaseous
ammonia from the atmosphere.
The soil will also absorb some am
mOnia from the air; but it seems
doubtful whether these actions can
fully account for the considerable
assimilation of nitrogen which APP
pears in the above experiments-an
assimilation which seems specially
associated with leguminous crops.
2. Deherain believes that the hui
mus of soils is capable, in the alb
sence Of oxygen, of combining with
the free nitrogen OF the air, which
he supposes, under these circum-
stances, to be first converted into
ammonia. This enrichment of the
soil with nitrogen, he believes,
takes place in the lower layers Of
the soil. The reaction in question
is very far from beng established.
Berthelot has recently made expert
ments, from which he concludes
that plants can assimilate free nj
trogen when exposed to certain
electrical influences. This action
also requires to be substantiated.
1t is clear from what has now been
said, that it is not only difficult
but impossible to express, with eX-
actness. many of the gains and
losses of nitrogen upon "a farm.