The Dickinson press., 1911-12-23
B0LLEY ON PLANT DISEASE
and CROP ROTATION

cultural college. %reorgnized all over the
world as the greatest authority on crop
rotation and crop disease. said in part
at the North Dakota Dry Farming Con-
gress held in Dickinson on December 7
and 8:
WHAT HAPPENS IN NATURE
In speaking of crop rotation, it is
always interesting to look about US in
nature and see what occurs there. If we
look at the woodland areas or to the
prairie areas or any undisturbed area
OF native lands, what do we find7 We
find there only those plants which are
able to live under the conditions.
There are usually quite a number of
different kinds. but comparatively few
kinds hold the chief control of the
ground against all of the others. These
plants represent ~typically what may be
spoken of as the survival of the fttest
under the natural conditions that have
arisen there un~infuenced by man. In
certain areas there are..heavy pine for
ests in certain other areas.heavy oak
forests. and in yet other regions large
areas of buffalo grass with a few scat
tering varieties of other types of grass
and light shrubbery. If one thinks of
plants which have grown on these areas
in previous times and studies the con-
ditions he becomes aware of the fact
that there has been a certain type of
what would seem to be essentially a
form of crop rotation in the plant world,
one crop of plants following another,
each gradually taking charge-.of the
ground and afterwards losing control of
it to yet a later form. For example, in
the lake and forest regions. ponds and
sloughs gradually. dry up. On their mar
gin the first land. plants are represented
by moses and bog plants followed later
by marsh plants. rough shrubbery and
later by real forests of the changing
type until the present form is attain
ed. which, in it's turn, may be seen to
be giving way to other forms which
heretofore have not apparently existed
in great numbers. Out on the prairie
lands where the forests could hot, be-
cause Of drouth conditions, gain a
start. the lake margins are first occupied
by light MOSES, then rushes. sedges and
marsh grasses. In the dryer regions
these PUSHES and sedges are finally
crowded out by the true grasses of the
alkaline loving type: these, later. by
real native grasses of the prairie includ-
ing some light shrubbery.
These conditions are, however. hardly
to be spoken. of as plant rotations.
Commonly there is no indication of a
return to tn" Original ferns. This only
happens when. there is a real change in
soil or climatic condition of long stand.
ing. Such occurrences are more
properly to be considered as PLAN
SUGGESTIONS. The plants now present
in particular areas. simply representing
the survival among those which have
developed there. The others have passed
out of existence or lost control simply
because the conditions are not suited fol
their kind but are more nearly suited tt
the kind which now occupy the land.
THE PRESENT IDEA OF CROP RO.
TATION
We may thus say that the present
idea of crop rotation rests upon fouI
essential facts which are c~onclusivel,
proved by the concensus of genera,
theories and results: /. A single crol
system is sure to fail in the long rur
because of inability of the land under
this condition to produce a s%ufficien,
crop to pay for the work 2. An ordi.
nary interchange of crops upon the lane
has in all ages been found 10 resulting
bigger and better yields for the variou:
kinds of crops. 3. The addition o.
fertilizers and especially of barnyard
manures and crops plowed under gener.
ally results in increased crops. Al
least. in an increased crop with regart
to some of the crops which are in thu
rotation and the increase of crop ha.
usually been sufficient to convince mos,
people that the manures should be used.
4. Leguminous plants should be anc
are placed in all rotations because sucf
plants enrich the soil by the addition
of nitrogen taken from the free nitrogen
of the air. These conclusions have
essentially been available to the farm.
ing public as definite information fol
at least twenty years and most of the
facts that the theory. of crop rotation
has not taken a stronger hold upon the
general farming public.
WHAT THEN ABOUT CROP ROTATION
AS USED IN THE CONTROL OF
ROOT RIOTS AND BLIGHT
OF WHEAT:
AS indicated in some of the late
publications of the Department o.
Botany. notably Press Bulletin 80, ant