THE OLIVER PLOW BOOK
permitted to mingle in such a way that the root system
can put forth new stems. Hence, the ideal system for
plowing sod is to see that all portions of the grass plant
are completely buried and the ground packed as closely
around these leaves as it is possible to do in order that
sunlight may be kept away from the turned over leaves.
One can rest assured that if there is a possible ray of
sunlight peeping through the turned furrow where the
leaf of wild and native prairie grass lies the blade of
grass will grow through that hole, hence the furrow slice
should be thick enough to keep out sunlight and air.
If this is done effectively shallow root crops such as flax
can be planted and they will act as an aid in the final
breaking up of the sod structure.
The kind of plowing the bottom illustrated above does. Observe the
furrow slice is laid over flat to keep all the air and light away from the
leaves and stems of the grass.
PLOW BOTTOMS tbl
Special plows are required for this purpose. The
shape of the share and mouldboard is such that the
furrow is turned over disturbing its composition as
little as possible. Illustration E shows this type of
The other influencing factor in reference to shapes of
mouldboards is sticky soils that do not have enough
body to hold together to give the amount of pressure
necessary to force the dirt off the mouldboard. Natur-
ally, in designing plows for work in this type of soil the
mouldboards and shares are designed to crumble the
soil as little as possible. The curvature is less pro-
nounced than in any other type of plow bottom.
There are various ways of explaining the crumbling
and crushing influences upon the earth as it passes over
the mouldboard, but a very simple explanation is found
in observing the distance that the top and bottom of the
furrow slice travel in the process of being picked up and
It is obvious that the bottom of the furrow slice
travels a much longer distance when being inverted than
the top or stubble side. This process of inverting the
furrow means breaking up the earth into particles.
Whether these particles are broken into larger or
smaller clods depends upon the tenacity with which they
stick together andj^the shape of the mouldboard for
The broad principle employed in shaping the curva-
ture of mouldboards is one that will cause the soil
granules to roll one upon another and thus break their
cohesion. A closely textured soil, plowed while wet,
increases the cohesions of the granules so that they will
not fall apart in the act of plowing. Thus a mouldboard
102. t %li e .^.THH. OLIVER PLOW BOOK
that does a perfect job of plowing in soil that is in the
proper condition for plowing will be ruinous to this soil
when plowing it too wet.
It is further obvious that those soils which must be
plowed when wet require the use of a mouldboard that
will break them as little as possible while being turned.
This characteristic identifies those types of plow bot-
toms used for plowing wet soils that do not have the
benefit of the winter's freezing.
The illustrations of the following plow bottoms will
suffice to make clear the efforts being put forth to build
bottoms suitable for all conditions.
Illustration F shows a steel base, general purpose
bottom. By general purpose is meant a plow that will
not only plow stubble, but also tame grass sods. The
shape of this bottom is such that it scours in a great
many varieties of soils. This bottom turns a furrow
well over and leaves an even, well crowned furrow top.
The types of soil in which this bottom gives the best
satisfaction are the sandy and clay loam, and some waxy
soils where scouring is a hard problem. This plow
bottom is well adapted to heavy loam and gumbo soils,
This ground was plowed with a bottom li^e the one shown in illustra-
tion F. The characteristics of this bottom are plainly discernible in the
provided the ground is not wet, or does not disintegrate
or slack when it comes in contact with air. Whenever
plowing ground where the furrow slices do not hold
together well this shaped bottom can be safely used.
On account of the shape and gradual turn of the mould-
board it does an exceptional job of pulverizing.
Illustration G is a long, slow turn bottom particularly
adapted to stiff clay soils and all classes of soils that
THE OLWER PLOW BOOK
f the plow bottom shown in illustration G. Observe that the
ground is very finely pulverized and the few clods are flat. The surface
of the ground is level; furrow crowning is imperceptible. The furrow
bant^ is smooth, the bottom is well cleaned, leaving an ideal surface for
the following bottom to lay the next furrow slice.
have clay in their composition. This bottom thoroughly
pulverizes clay if the soil is in a condition to be plowed.
The shape of this mouldboard is such as to cause the
earth to separate in layers rather than to break into
lumps. It is distinctly noticeable in a field plowed with
this bottom that the few clods left are always flat shaped
and very frequently will fall into pieces when picked up.
Naturally, a bottom that does this kind of work requires
more power than one which does not pulverize the
ground as effectively.
Illustration H is a general purpose bottom made
specifically for work in all types of clay and sandy loam
that are hard to penetrate. It is also the most desirable
bottom for use in these same types of soil full of
gravel, cobblestones and shale or flat stone. This
bottom is made with a narrow breast which permits the
of the plow bottom as shown in illustration H. In view of
the fact that it is necessary to aerate soils when they are being plowed a
plow bottom to work in this type of soil must be designed to prevent stones
from throwing it out of the ground the least number of times and when
it is thrown out to penetrate quickly- This type of bottom does this work
THE OLIVER PLOW BOOK
use of a strong and well tapered share required for stony
lands, consequently this bottom will penetrate this kind
of ground and thoroughly stir it which is necessary if the
oxygen in the air is to mix freely in the ground. This
kind of plowing cannot be accomplished in these soils
with an ordinary bottom. The narrow breast and the
high delivery mouldboard insure the earth being well
mixed in the process of plowing.
Illustration I is a general purpose bottom. This bot-
tom is made to plow the volcanic ash soils that are found
The work of the plow bottom shown in illustration I. Observe the
deep furrow wall and the well turned furrow slices.
PLOW BOTTOMS 107
in the northwestern section of the United States. In
plowing these peculiar types of soils the farmer fre-
quently desires to plow deep. This can be accomplished
with this bottom. The shape of the mouldboard is
curved so as to pulverize this type of soil exceptionally
The slat mouldboard gives less surface, hence less earth sticks. For
this reason the slat bottom serves a good purpose.
Illustration J shows a slat bottom. There are soils
so sticky by nature that the ordinary plow bottom will
not scour. These soils will not hold together sufficiently
to give enough pressure against the mouldboard for
scouring. The slat bottom eliminates a part of the
mouldboard. Therefore, there is not so much surface
to which the earth may stick. For this reason a slat
bottom will scour and do a good job of plowing where a
solid mouldboard entirely fails. These bottoms are also
exceedingly useful for plowing black, waxy and clay
soils in which an ordinary plow bottom fails to scour.
The share is made with a comparatively straight edge
to give a straighter cutting surface to the share.
THE OLIVER PLOW BOOK
Illustration K is a stubble bottom designed for use in
waxy soils and the lighter prairie soils where scouring
troubles prevail. This bottom is particularly adapted
to work in those soils that have a tendency to stick to
the mouldboard, but are rather loose in their composi-
tion. For this reason the share and mouldboard are
shaped to cause as little breaking of the soil as possible
until it leaves the mouldboard. The furrow is turned
A type of soil in which the above illustrated mouldboard is in common
use. A glance at this picture is sufficient to show that the plowmaker's
problem is a difficult one.
slightly more than half over. On account of these
features this bottom is not adapted to plowing sod. The
unusually sharp point and narrow angle formed by the
landside and share give this bottom great penetration,
a feature which is absolutely necessary in the types of
soil to which this bottom is adapted. The shape of the
share and mouldboard is such that the earth exerts an
even pressure upon the bottom from the time the share
strikes it until it is turned over on the furrow side.
Illustration L depicts a bottom popularly known as a
Scotch type and is for use in turning soils in those
countries where clay land predominates and where rain-
fall is excessive. The share is narrower than the mould -
The work of the plow bottom shown in illustration L reveals that the
earth is turned over with little or no pulverizing. This is necessary for
underdraining and to give the furrow slice on top an opportunity to dry
out so that it can be successfully tilled.
1 10 THE OLIVER PLOW BOOK
board, consequently, a portion of the furrow is not cut
entirely off. The mouldboard pushes the cut part of
the furrow solidly against the preceding furrow, shaping
the furrow to leave the top diamond shaped, and drain-
age facilities on the bottom.
Illustration M shows a chilled bottom made for
handling all kinds of gritty, sandy soils, and also clay
lands that are not sticky. This bottom is made with a
sloping landside. When the plow picks up the dirt to
turn it over, the lower outside edge of the furrow slice
acts as a fulcrum over which the furrow turns. When
the furrow is raised into a position almost vertical the
dirt falls of its own weight because there is nothing to
prevent its downward motion. As the earth begins to
fall it naturally crumbles, filling the lower portion of the
furrow with loose pulverized soil. The advancing mould-
board finishes the work by turning the rest of the
furrow on top.
This process of plowing is exceptionally good for
sandy soils because it insures a thorough circulation of
air in all parts of the furrow slice. Another advantage
of the sloping landside is that the shin acts upon the
earth very much in the same manner as a knife
acts upon a piece of wood when operated with
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1 12 THE OLIVER PLOW^BOOK
a slanting cut. This also has a tendency to make
the plow pull lighter in draft than a plow with a
These few illustrations serve to show that it is highly
important to select a plow bottom for handling the soil
the way it should be, and also that when any doubt
exists to consult a plow expert before a radical change
is made in bottoms.
Generally speaking, the type of plow bottom that
does the best work pulls the hardest because the old
law that so much energy is required to produce a given
amount of work is applicable to plow bottoms. Less
power is required to break a clod into three parts than
into a million. The breaking of earth into finer particles
is highly important if the proper seed bed is to be
Tests have been made which show that mouldboards
curved to do the pulverizing require more energy or
power than the bottoms which break the soil into
clods. The four illustrations showing sectional views of
plowing are the results of a test made purposely to deter-
mine whether the plow bottom that did the best pul-
verizing pulled heavier than the one that did the inferior
grade of work. This test was made in a field of very
heavy clay and sand not in a loamy combination. It
had not rained for several weeks. All the tests were
made in the morning of the same day in order that there
should be as little change as possible in the moisture
content of the ground. The only difference in the plow
bottoms was in the shape of the mouldboards. Thus, the
condition for all the plows was the same, the only dif-
ferent contributing factor being the mouldboard.
Not e the thorough pulverization of the soil, the foot prints which show
the dry condition, and the absence of air spaces.
Figure 1 shows a job of plowing almost ideal. One
would not expect it in soil as dry and hard as this but
the plow pulled 14% heavier than the plow bottom
which did the poorest work, or that shown in Figure 4.
This plowing is not so well pulverized as that shown in Figure I , but
it could be regarded as a fairly good job of plowing dry soils.
The plowing shown in Figure 2 is not so good as that
Figure 1. The ground is not as finely pulverized.
The plow bottom pulled 4% lighter.
THE OLIVER PLOW BOOK
The clods are larger than those shown in either of the two previous
illustrations. The air spaces at the bottom of the furrow slice are more
pronounced, and the furrow slice shows cloddy formations rather than
The work in Figure 3 shows that the earth was
turned up into clods. There is little pulverization.
The bottom used in doing this work pulled 13% lighter
than the one that did the work shown in Figure 1 .
Clods are larger than in Figure 3. The furrow slices are unevenly
formed. They are merely larger clods intermingling with smaller ones
and the finer soil particles. There is no indication of pulverization
which is necessary for the proper aeration of the soil.
The plowing done in Figure 4 shows the ground broken
into large clods, little or no pulverization and very im-
perfect furrow slices. This job required less power by
1 4% than the one shown in Figure 1 .
PLOW BOTTOMS 1 1 5
When one considers that the pulverization of the soil
is vitally necessary in by far the greatest number of
cases he will pay less attention to the draft of the bottom
and more to its adaptability. Sufficient power should be
used to do the work well.
An experiment was made with the bottoms shown in
illustrations F, G, K and M to determine just what effect
different shaped mouldboards have upon the soil. This
experiment was made in a field of clay soil thoroughly
saturated with water. It was necessary to perform such
an experiment with a soil that would hold together
sufficiently to make observations. Wet clay is the best
kind of soil for this purpose.
These four types of plow bottoms are for use, as the
descriptions read, in widely varying soils. The illus-
trations of the work done by these bottoms in the soils
for which they are adapted, when compared with these
illustrations, must forcibly call attention to the impor-
tance of selecting a plow bottom adapted to the soil.
These experiments were conducted in the morning of the
same day in order that the moisture content should be as
nearly uniform as possible.
These illustrations also show the relative work done by
the share, mouldboard and landside in such a way as to
call attention to the difficulty encountered in trying to
establish a fixed center of draft that will serve as a guide
for all shaped plow bottoms and soils.
While this question would be more properly discussed
in the chapters on plow hitches, these illustrations are so
pertinent that the reader's indulgence for this deviation
from good sequence is asked.
THE OLIVER PLOW BOOK
The right-hand side of the furrow slice is laid on the furrow bottom
in such a way that the forward travel of the mouldboard will give it a
pinching, crushing motion to separate the soil particles.
In the seventh paragraph of this chapter the plow
bottom is referred to as a three-sided wedge.
The mouldboard and upper part of the share form the
curved wedge shape part which separates the soil parti-
cles while turning them over. For the sake of clearness
in this discussion the work of the plow bottom is divided
into three parts: first, the share, cutting the furrow sole;
second, the shin, cutting the furrow wall; third, the
mouldboard, lifting, stretching, turning and compacting
the furrow slice into an inverted position.
The relative amount of work that the shin, the mould-
board and the share do is exceedingly hard to figure. It
is very doubtful whether an absolute center of draft can
A section of the furrow shown in the illustration on page 116 cut
farther forward, showing that the plow bottom has forced the furrow
slice to conform to its shape, thereby beginning a stretching operation on
the bottom of the furrow. Observe in the illustration on page 116 that
after the furrow slice has reached the ground the freshly stretched
furrow slice bottom is helping to put pressure against the top.
A plow bottom which does not have the proper shape to force the
furrow slice against its surface so that the pressure is equal on all parts
of the plow bottom. This illustration shows the importance of having
a plow bottom adapted to the soil. The shin is doing the greater part of
THE OLIVER PLOW BOOK
The work of this bottom shows remarkable adaptability to this type
of soil. The squeezing, pinching motion of the mouldboard by forcing
the furrow slice against the bottom of the furrow is plainly noticeable.
This mouldboard is doing more work than the one illustrated on page 120.
be determined for all conditions. Enough experimenting
has been done to show that the center of draft can be
approached closely enough for practical purposes.
When once the center of draft has been determined it
is obvious that the amount of work being done on all
sides of this point must be equal in weight. Measuring
the distance from this point to all the extremities of the
mouldboard and share will give sufficient measurements
to figure the percentages. The result will be close
enough for all practical purposes.
The furrow slice shown in the illustration on page 118 cut farther
forward. The plow bottom forces the furrow slice against it in such a
way that the complete furrow slice taJ^es on the curvature of the mould-
board. This means a rearrangement of the soil particles from the top
of the furrow slice to the bottom.
Another way for determining the relative draft of the
share and mouldboard is to remove the mouldboard from
the plow, then start the plow in a furrow the proper
width and depth previously prepared with the end of
the furrow slice cut squarely, and the furrow wall the
depth of the furrow far enough ahead for the experiment.
A. dynamometer will show the relative lifting work done
by the point and wing of the share. The plow must
stop as soon as the earth has been lifted the height of
Putting the mouldboard back on the plow, and lifting
the furrow slice which has been measured the proper
width and cut the full depth until it is ready to drop into
position, will obviously determine the amount of work
required by the share and mouldboard. Subtracting
the difference between this amount and that required by
THE OLIVER PLOW BOOK
The furrow slice is being picked up and turned over very much as a
cal^e of ice, without any perceptible pulverization of the ground. Observe
that the bottom of the furrow slice does not rest against the furrow bottom
except the loose particles that have broken off and have fallen down.
Observe the center of draft on this plow is lower than the one shown on
the share will give the amount of work done by the
mouldboard. Using the entire plow without cutting the
furrow wall gives the amount of work required by the
shin to cut the furrow wall, the share, the sole, and the
mouldboard to crush and invert the furrow. Experi-
ments of this kind have been conducted with widely
A test was made using what is known as the Scotch
type of plow bottom. The ground, clay sod, was being
plowed six and one-half inches deep and eleven inches
wide. The amount of work done by the share was forty
per cent, of the total, the lifting and placing by the
mouldboard, forty per cent, and cutting the furrow wall
by the shin twenty per cent.
The furrow slice the same as shown on page 120 cut farther forward.
This furrow shows no indication of pulverization but a tendency to lift
the slice from the start.
Another experiment with an entirely different shaped
bottom cutting six inches deep and fourteen inches wide
revealed the following result. Thirty-three per cent, of
the work was done by the share, forty-seven per cent,
by the mouldboard, and twenty per cent, by the shin
cutting the furrow wall. The type of soil in which the
experiment was conducted was a clay loam sod.
In both instances the draft of the plow was arranged
so that there was no pressure of the landside against the
The amount of work required of the landside is solely
determined by the hitch. If the hitch is properly made
there is little landside pressure because the land suck on
122 THE OLIVER PLOW BOOK
A type of mouldboard which breads this wet clay soil into large clods.
Notice the bluffness and the effect upon this soil. It ought not require
any argument to show that this plow is not adapted to this type of soil.
Breaking soil into clods is not plowing.
the share and shin cuts away the earth, leaving the land-
side free from coming in contact with the furrow wall.
However, in actual practice this condition does not pre-
It has been found that the pressure of the landside
against the furrow bank caused by incorrect hitching
increases the total draft of a plow bottom from fifteen to
forty per cent., depending upon the kind of soil being
plowed and the distance the hitch is away from the
center line of draft.
This statement with reference to the pressure of the
landside immediately suggests the point, why have a
landside on a plow if there should be no pressure against
the furrow bank ? There must be some means for keep-
ing the plow from swerving to one side whenever the
share strikes some obstruction that causes a sudden
shifting in the center of draft of the plow bottom. For
In view of the fact that breaking the soil particles is necessary for
the proper making of the seed bed, the question often confronts those who
have stony ground as to how they can plow so that the bottom will pene-
trate the ground immediately after the stone has been passed. The illus-
tration shows how one farmer is accomplishing this work- On account
of the rapidity with which this type of soil dries out it is highly im-
portant that there be the fewest possible unplowed stretches of ground.
example if a plow should strike a snag on the wing of
the share the center of draft of the plow is suddenly
changed to a point near the wing. The landside press-
ing against the furrow wall holds the plow in its true
THE OLIVER PLOW BOOK
Turning an in-corner has been practiced by farmers who have soils
that should not be trampled any more than is necessary in the process of
plowing. It is highly important that the furrow be turned so that the
ground is plowed properly if the best results are to be obtained from this
line until the obstruction is passed and the center of
weight returns to its normal position.
As a matter of fact, this condition is constantly taking
place in the soil. The soil texture changes with every
inch of travel and some means must be provided to take
care of rapid and continuous changes. The shape and
size of the landside have a great deal to do in this con-
nection. Obviously there must be enough square inches
This clay field is being plowed seven inches deep to permit moisture
to escape. This field was tiled but on account of the imperciousness of
the clay excessive water remains and it is necessary to plow in such a