The Northern Pacific farmer. [volume] (Wadena, Minn.) 1878-1885, 1880-08-12
Agricultural.
Exhaustion Of the Soil.

The FARMER has often cautioned
the people in the rich Northern Pa
cific country that there is such
thing as exhausting the soil OF their
now remarkably productive farms, by
q continual drain upon them without
at least some effort to return a pOr-
ton of their strength. The follow
ing article upon the subject, from
the pen of DR.. J. B. Lawes, an En-
glish agreculturalist, may contain
some valuable ideas for the consider
alton of our thinking farmers: ''It is
now exactly forty years since we be-
gan to exhaust portion of one Of my
fields by continuous lmman,ued wheat
crops. It may therefore be inter-
esting to show the evidence we are
in position to bring forward upon the
subject of exhaustion as regards the
soil at Rothamsted. It would appear
probable that the annual decline
due to exhaustion may amount to
from one-quarter to One-third Of a
bushels of wheat per acre per ann'lm.
If we take the smaller quantity and
add to it the ordinary proportion of
straw, the result would be equivalent
to about 40 pounds of produce; and,
as there is but little doubt that the
bulk of the organic matter of the
crop is obtained from the atmosphere.
the amount Of matter annually taken
from the soil by these 40 pounds of
produce Gncluding the nitrogen it
contained) would be between two
pounds and three pounds. The ev-
idence derived from other expert
ments in the same field proves that
the decline in produce is due to all
absence of nitrogen, as also that min
erals are in excess, but the actual
amount of nitrogen that these 40
pounds of produce would have con-
tanned would be less than one-half
pound in weight! 1t will, lam afraid.
appear to your agricultural readers
something like an absurdity to suppose
that one-half pound, more or less. Of
any substanc upon an acre Of land.
could have all appreciable influence
upon u crop. l may observe, how
ever, that this annual decline Of 10
pounds of product, small as it appears
to be. amounts in forty years to 10
bushels per acre. Analyses of the
soil made ut different times show that
the nitrogen is declining, and as the
free use of minerals, in an adjoin-
ing experiment does not prevent the
decline of the crop. we can come to
no other conclusion, than that the
gradual decline in the produce is due
to the diminishing amount of nitro
gen in the soil. AS far us the wheat
crop is concerned, it will appear that
the total ;aMo mt of produce to be OBJ
tanned from amy soil must depend
very much upon the stores Of nitro
that the soil obtains a certain amount
of ammonia from the rainfall. and it
probably condenses more or less from
the atmosphere; but on the other
hand, drainage carries away every
wear more or less nitrogen in the
form Of nitric acid; and it is evident
the atmosphere supply, whatever it
may amount to, does not suffice to
prevent a decline OF the crop; it is
therefore also evident that the source,
from which the forty crops obtain
their supply, must have been the
stores of nitrogen already existing in
the soil when the experiment COM
menced; further it seems most prob
abe that the yield of future crops
viii! depend upon tire amount OF nitro
gen liberated each year from the soil.