The Prince George's enquirer and southern Maryland advertiser. (Upper Marlborough, Md.) 1882-1925, 1896-06-12

and potash and, on my particular soil
the occasional use of the subsoiler, is
necessary. / have therefore determin
ed on the adoption of a longer system
of general rotation Of crops which will
enable me to introduce a rotation OF
leguminous, as well as of grain and to
bacco crops, SO that clover will not be
sown oftener than QUE year in seven
on the same land. My reasons fol
this will appear further on.
Our principal fertilizing agencies
are barnyard manure, green crops
turned under, and commercial fertili.
zers, the chief plant food elements OBJ
tanned therefrom being Potash, Phos
phoric Acid and Nitogen. The two form,
er are most economically v obtained from
the commercial fertilizers while Nitro.
gen, which is the most expensive elt-
ment of plant food, is most economi-
cally obtained by the growth of Legu-
minous Plants, i. e., Red Glover, White
Glover, Vetches, Lucern, Peas, Beans,
Etc, which benefit the soil by increas-
ing in it the amountof nitrogen availa-
BILE for the use of other plants, such as,
grain and tobacco. Now how do they
do this? From what sources do they
obtain the supply, and in what ways
do they make it available as plant
food? Many experiments covering
long periods of years have been made
by scientific men in Europe and Amer
ica, with the view of determining these
points, and it is very interesting to
note the gradual development of know
ledge on the subject. "There is OF
course, nothing new in the fact that af-
ter the growth of a leg luminous crop,
such as red clover for example, the
soil is left in higher co ndition for the
subsequent growth of a grain crop and
that in fact the growth of such a legu-
minous crop is to a gre at extent, equi-
valent to the application of a nitroge-
nous manure for the sera |. Indeed
history tells us that more than two
thousand years ago it was recognized
by the Romans that the occasional
growth of plants Of the leguminous Or
der had the effect of increasing the
growth of the graminaceous crops with
which they were alternated and it was
stated that the effect was equivalent to
that of applying manure. Thus, Varro
says that certain things are to be sown
not with the hope of any immediate
profit being derived from them, but
with view to the following G year, be-
cause being plowed in and then left in
the ground, they render the soil after
wards more fruitful, and the plants
used for this purpose were lupines,
beans, yetches, and other legumes."
"The problems in the matter of the
sources of nitrogen of our non legumi-
nous crops of barley, wheat and grasses,
of turnips, beets and potatoes, etc.,
have long since been solved. The COM
bined nitrogen is taken up by these
crops as nitric acid, or rather as nj
trates and is available from the stores
already existing within the soil and
subsoil or those provided by manure
and in addition small amount annu-
ally coming from the atmosphere in
rain. 1t was admitted, however, that
the existing evidence was insufficient
to explain the source Of the uhole OF
the nitrogen of the leguminous plants
which is so many times greater than
that of the other classes. There was
in fact a missing link! 1t is nearly Il
century since the question whether
plants took up or evolved free nitrogen
became matter of experiment and
of discussion, and it is generally adj
mitted that all the evidence that has
been acquired on lines of inquiry until
recently toUored has failed to solve the
problem. During the last few years,
however, the discussion has assumed a
somewhat different aspect. 1t is now
supposed that free nitrogen is brought
under contribution in various ways, es-
pecially by being brought into combi-
nation under the influence Of micro-Or-
ganisms, or of other low forms, either
within the soil itself, or in symbolic
growth with higher plant. Many
and careful observations
were made before the conclusion was
reached, ''that many plants may ac-
quire nitrogen brought into combina-
ion under the influence of lower Or
ganisms, the development of which is
in some cases: a comcident
of the growth of the higher plant
whose nutrition they are to serve"
''It was in the Agricultural Chemis-
try Section of the Nat urforscher Yer
neld in Berlin in 1886, that
Professor Hellriegel first announced
his new results. Quite consistently,
not only with common experience i'll
agriculture, but also with the direct
results of others, He'll
riegal found that plants of the grami-
neous (grains and grasses y the Cheno-
ipodaceous (beets,) the Polygonaceous