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'HE treatment of any farmer's
soil is entirely within his hands.
Success is measured by his
knowledge and the diligence with which
he applies those laws of Nature which are
related to crop growing.
These laws are universal. A farmer
can apply them to meet his own partic-
ular need better than acting upon the ad-
vice anyone can give him, because he
understands his soil conditions. Other
people do not.
The purpose of this book is to set
forth these laws and explain the causes
The Oliver Chilled Plow Works has a
desire to be of practical value to farmers.
Our long experience in building plows and
kindred implements for use all over the
world has given us an opportunity to ob-
serve a great many facts in connection
with plows and plowing which should be
common knowledge among farmers.
OLIVER CHILLED PLOW WORKS.
I. Functions of the Plant Organs 5
II. Influence of Water 14
III. Importance of Air in the Soil 27
IV. Soil Temperature 32
V. Why Soils Must Be Handled Differently 37
VI. Depth of Plowing 51
VII. When to Plow 63
VIII. Plowing to Kill Insects 72
IX. Plowing to Kill Weeds 79
X. Plowing Under Green Manure 87
XI. Judging Plowing 92
XII. Plow Bottoms 97
XIII. Plow Bottom Metals 129
XIV. Scouring Troubles 137
XV. Setting the Share on the Plow 1 49
XVI. Sharpening Soft Center Steel Shares. ... 154
XVII. Sharpening Crucible Steel Shares 158
XVIII. Sharpening Chilled Shares 159
XIX. The Rolling Coulter 160
The Combined Rolling Coulter and
XX. The Tractor Plow Hitch 167
XXI. Adjusting Horse Plows 183
XXII. Middle Breakers 189
XXIII. Disk Plows.. 195
Functions of the Plant Organs
' I "HERE is a vast difference between operating a farm
* and a factory. The process of manufacture from the
receiving of the crude materials to the finished product
is entirely in the hands of the manufacturer. That is,
he can control every step in any process from start to
finish. It is not so with the farmer. The farmer can
control only the operation of the machinery. He has
to have a partner to enable him to successfully grow
crops. That partner is mother Earth. He has to
depend upon her for everything except the labor, which
is his part of the contract.
Obviously the farmer who succeeds best must under-
stand Nature. It is a hopeless task to learn all the
whims and caprices of Nature, but it is possible to learn
how to treat mother Earth so that she can use these
whims and caprices of Nature to bring forth bountifully.
The first step in this process is plowing. Many
important historical events offer the strongest evidence
that from the time man first began to till the soil he
discovered the necessity for stirring it in some manner
before any kind of a crop could be grown. Even the
greatest authors of antiquity, medieval and modern
times, speak of plowing. We have Benjamin Franklin
in our own colonial times who advised farmers "to plow
deep while sluggards sleep and you will have corn to sell
and keep." Pliny spoke in his treatise on agriculture,
&!'<< -THE OLIVER PLOW BOOK
of the importance of having the ground properly pre-
pared, and even in the New Testament, in the book of
St. Luke, the parable of the sower forcibly illustrates
that Christ was a keen observer of the laws of Nature
as related to crop growing.
"A sower went out to sow his seed; and as he
sowed some fell by the way side; and it was trodden
down, and the fowls of the air devoured it.
And some fell upon a rock; and as soon as it was
sprung up, it withered away, because it lacked
And some fell among thorns; and the thorns
sprang up with it, and choked it.
And other fell on good ground, and sprang up,
and bare fruit a hundredfold."
This quality to observe conditions as they are is just
as fundamental to the business success of any man as
it is for his religious welfare. There is not such a
tremendous amount of difference.
Evidently farmers in Christ's time believed that it
was necessary to kill the thorns and to conserve moisture,
and they believed still more that it was necessary to
have the ground "good." This word "good" involves
a great deal. Our modern soil phycisists tell us that we
plow to kill weeds, conserve moisture, and to put the
ground in a good condition of tilth. By tilth they
mean that the land is in shape to be cultivated easily
and in such condition as to bring forth abundantly.
Before one can put ground in condition to meet plant
growth requirements he must have a thorough under-
standing of the habits and characteristics of plants he
desires to grow, the kind of food that plants require and
FUNCTIONS OF PLANT ORGANS
A fully matured corn
plant showing the parts
that have to do with the
growth of the plant.
Observe the short root
system compared with
the network f roots of
the four hills of growing
corn illustrated on page
THE OLIVER PLOW BOOK
the soil conditions necessary for the manufacture,
maintenance and proper distribution of that food to the
plants as they need it.
Botanists tell us that every part of the plant has
functions which it performs for its own development.
The functioning of the various organs of the plant is
naturally very different from that of the animal, never-
theless, these organs are just as important to the plant
as the digestive and breathing organs are to the animal.
The greatest of care is exercised in feeding the stock.
The proper amount of food and water is given to the
animals at the right time. In the summer the green
pastures supply the great percentage of food for cows.
In the winter they are given foods which produce milk
and flesh. If horses are being used in the field they are
fed the kind of food that keeps them strong and healthy.
The same rule holds true of the entire animal family.
No two types of animals ever receive the same kind of
food nor even the same portion; that has to be given
according to their kind. The same feeding law holds
true of plants.
Plant life is different from animal life. The animal
is either fed by human hands or goes about searching
its own food. The plant is stationary. It, therefore,
must subsist upon the food contained in the air and
soil within reach of its organs.
All crop producing plants have roots, stems, leaves,
and flowers, or the fruit. The farmer is concerned as
to the quality and quantity of fruit produced. The
quality and quantity of fruit are determined by the
growth of the leaf and stem, and also the plant's ability
to withstand the evil influences of wind, drouth and
FUNCTIONS OF PLANT ORGANS
The seed of any plant is supposed to contain enough
nourishment for growth until the roots are large enough
to drink in their nourishment from the surrounding soil,
and the stem to break through the top of the ground to
breathe in the required air.
The roots are the organs that search out into every
particle and recess of the soil within reach for plant
food, and carry it to the stem.
The most important part of the crop growing opera-
tion consists in bringing about a soil condition whereby
the seed can germinate according to its natural inclina-
tion and the plant produce a root system necessary for
vigorous growth and flowering.
The little kernels in the wheat illustration were
sprouted to show how little and tender are the roots
of germinating seeds.
Four kernels of sprouted wheat. The two outside ^ernc/s would
sustain the plant until the roots and stems could feed themselves. The
two inside plants were weak seeds. The seeds are entirely consumed,
and the young plants are not large enough to support themselves.
10 THE OLIVER PLOW BOOK
It is important that a seed bed be in a well pulverized,
compact condition for the sprouting of seeds and grow-
ing of plants. The little kernels of wheat must sprout
and grow, but before they can do it the plant food must
be in the soil in available form for the little tender
roots to feed upon. Observe the sprouts running up
and the little roots going downward. One pinch of the
root with the fingers would kill it, yet, it is supposed to
grow and produce tenfold times. There is food enough
within the kernel, if it is good seed, to nourish the grow-
ing plant for a short time, but after that it must reach
out into the soil to find sustenance, and if that plant
grows rapidly it must have the food within convenient
reach just when it needs it. This is the great reason
why the preparation of the seed bed is the most im-
portant part of the crop growing operation. It matters
not how good the seed, if the soil is not in the right con-
dition to make plant food available to nourish the
starting plant, growth will be stunted. Pulverizing the
ground when plowing is the first and most vital step to
accomplish this end
There is another reason why a compact seed bed is
necessary. After the seed has sprouted, and the plant
has acquired its growth, more food is necessary for the
flowering of the grain. The roots are searching through
the ground by means of their continued growth to find
this food. The better the seed bed is pulverized, the
more available food the roots find. They form a net-
work of food seekers entirely occupying the ground from
one plant to another.
The corn field illustration, in which the rain has washed
away the earth from the roots, shows the interweaving
of the root system of corn. Each of the little hair
FUNCTIONS OF PLANT ORGANS 1 1
roots drinks in its share of food for the plants. When
we consider that plants are soup eaters, that is, all the
food the roots absorb is taken in liquid form, the im-
portance of having the best possible seed bed from top
to bottom is obvious.
When the rain washed away the earth it generously left the corn roots
in much the same position as they would be found if it were possible to
look, into the earth.
A study of this illustration shows how easy it is to break these roots
by cultivation. Recognizing that roots are necessary for absorbing (he
food contained in the soil, the importance of protecting this root system
and giving it every opportunity becomes apparent.
The stems are the conveyors of this food to the leaves
and the flowers and also serve the important purpose of
holding up the flowers and leaves from the ground to
give them an opportunity to do their work.
The leaf has four principal functions to perform. It
has to do with the starch making properties of the plant,
12 THE OLIVER PLOW BOOK
the assimilation, the excretion of water, and breathing.
The functions of the leaves in these four processes in-
volve a very complicated chemical process which is not
very thoroughly understood and does not need to be
from a practical standpoint.
The only thing necessary to know is that a plant, to
flower and produce the proper grain, must have an
abundance of moisture in order that the sunlight and
air may supply the proper gases and heat necessary to
bring about these chemical changes. The task of the
farmer is to see that air, water and the proper plant food
elements are properly proportioned in the soil. He need
not worry about the part that surface air plays in the
growing of the plants because it is beyond his control.
Nature always supplies it abundantly on and above the
earth's surface. To be of the utmost value air must be
permitted to permeate every particle of the seed bed.
The tiller of the soil must see that the proper amount
of plant food is supplied during the plant's life so that
the entire plant can perform its functions. He must
not forget also that a plant, even as any animal, can
gorge itself so that one part of it will grow to the detri-
ment of another.
The plant may be considered in part as its own food
manufacturing establishment; that is, certain of the food
elements coming from the soil are mingled with the
gases which come through the leaves in such a way as to
form the starchy substances of the plants. It is vitally
necessary, therefore, that both the soil and air supply
the proper elements for these processes to take place in
The amount of plant food contained in water is very
small, hence, the plant must consume an immense
FUNCTIONS OF PLANT ORGANS 13
amount of water to derive the sustenance necessary. A
grass plant has been found to give off its own weight in
water every twenty-four hours in hot, dry summer
weather. This would make about 6J/2 tons of water per
acre for every twenty-four hours in ordinary grain fields.
This proves that moisture is one of the most essential
items for producing plant growth and must be properly
Botanists maintain that 95 to 97 per cent, of all the
materials from which Nature builds the tissues of her
plants are taken from the air. It is important, then,
that we know by what process the materials from the
air are transformed into plant food, particularly that
part of the process which Nature depends upon tillage
and the soil to perform.
Nature furnishes the moisture, air, light and soil.
She expects us to till the soil in order that she may use
the moisture, air, light and soil to the best advantage in
transforming materials into plant food for growing
crops. She rewards bountifully those who work with
her, and she recompenses poorly those who do not.
Working with Nature means a knowledge of the effect
of moisture, air, light and heat upon the soil and apply-
ing that knowledge in a practical manner.
Influence of Water
WATER is the greatest single factor in plant growth.
It seldom rains at just exactly the right time for its
use. The task is to keep this moisture where it can be uti-
lized by the growing plants just as rapidly as they need
it. Before this can be done successfully one must have a
knowledge of the characteristics of the different types
of soils, their capacity for holding moisture and the
rapidity with which it percolates and evaporates, also
the things that are necessary to permit moisture to sink
into the ground and keep it from escaping.
Water is the solvent of mineral elements in the soil
which nourish the plant, and since plants can absorb
mineral salts only in solution, water is absolutely nec-
essary to enable the plant to take nourishment from the
Water is the means whereby plant food elements are
transformed into plant food because without it there
can be no chemical action or reaction to transform the
elements into plant food. Water also holds in solution
food for the plant, carries it from the hair roots to the
stem, and from the stem to the places where growth is
taking place, transports plant food from one place to
another in the soil, and is a temperature regulator for
From 75% to 90% of the fresh substance in crops is
water, thus water in itself is plant food and essential to
INFLUENCE OF WATER 15
plant life. The greater part of this per cent, enters the
plants through the roots.
The 75% to 90% of water making the fresh substance
of plants is water in plant composition, and can only be
taken from the plants by excessive heat. However,
this water in composition is dependent upon the
amount of moisture contained in the soil and the humid-
ity of the atmosphere because the growth of the plant is
retarded or advanced as the amount of moisture in the
soil is available. This moisture in turn is controlled
more by the soil than the atmospheric temperature.
Hence, it is necessary to have moisture in the ground in
the right proportion for regulating the heat to retard the
process of evaporation as well as to promote the develop-
ment of plant food.
It is impossible to definitely define what amount of
moisture is required for the growth of a plant because a
great many conditions enter. A crop may require 300
tons of water for growth to maturity. It may be nec-
essary for the soil to furnish 350 tons on account of
varying conditions. Some the farmer can control,
others he cannot. Water that must be supplied for the
growing crops includes that which is constantly evapor-
ating from the ground and also that which the leaf and
stem of the plant are giving off.
The amount of plant food in water is very small; that
is, the solution is in a very diluted form. For this
reason a plant consumes many times its weight in water
to get the necessary food.
The principal factor which determines the water
requirements of a plant is the humidity of the atmos-
phere. In climates where the atmosphere is moist the
water requirements for the plants are much less than
16 THE OLIVER PLOW BOOK
those in dry climates. The reason for this is the amount
of evaporation from the leaves and stems. The more
humid the atmosphere the less moisture it takes from
the plants, the dryer the atmosphere the more moisture
it draws from the plants. If the atmosphere were
thoroughly saturated at all times the water require-
ments for the plants would be very small because of the
light transpiration of water from the soil.
Another peculiar fact in connection with the water
required is shade. Shade increases the amount of
water required for plant growth. It retards the
process by which the plant constructs its tissues because
the rays of sunlight necessary for this process are dimin-
Soil fertility has a great deal to do with the amount
of moisture required to grow a crop. A poor soil requires
more water than a rich soil for the simple reason that
the more fertility there is in the soil the stronger the
water holding content. A soil may be fertile in all the
elements but one. The lack of this one causes the soil
to require more moisture because growth is retarded
when a plant fails to get any one of the elements neces-
sary. The plant keeps on using and giving off water
exactly the same as though all the elements were in the
The great problem is to catch and save as much of the
rainfall as pdssible. The ground below the seed bed
must act as a reservoir to hold enough water for it to
come upward by capillary attraction to the root bed
and not escape into the air.
Capillary water is that which adheres or clings to the
surface of the soil grains and to the roots of plants in
films thick enough to allow surface tension to move it
INFLUENCE OF WATER 17
from place to place. It is Nature's means of keeping a
constant supply where plants can use it. Capillary water
is the chief source from which plants derive their supply.
So important is capillary water that crops grown on
moderately fertile plots where water was supplied as
fast as plants could utilize it, produced more than four
times as much as the same crop grown in an adjacent
field under ordinary conditions. The reason for this is
simply that during all the growing period rains do not
come at the right times. This naturally prevents the
plant food from becoming available every day as the
growing plants demand. It is like stuffing a boy one
day and expecting him not to get hungry for a week.
Feed the boy what he needs each day, and he grows into
a strong man. So it is with plants.
The picture (A) of the tube filled with fine soil particles
with the clods in the center illustrates very common
conditions in plowed ground. The clods in the center
prevent capillarity between the upper and lower portion
of finely pulverized soil. Consequently, the moisture
THE OLIVER PLOW BOOK
from below cannot reach the pulverized soil above the
clods any faster than the rays of light and heat evaporate
from above. This is plainly noticeable in the views
showing the water at different heights in the tubes.
In illustration B observe that the water has traveled
upward in the tube to a level much higher than the
water in the pan, showing the force of capillary action.
Also observe the firmly compact condition of the earth
as far as the water has traveled.
This is the way plowing is generally done. The large air spaces at
the bottom of the first furrow slice and the smaller one in the bottom of
the third are often found in fields that have been harrowed and are sup-
posed to be ready for planting. These air spaces interfere with the
upward trend of capillarity just exactly as is shown in the tubes on page
The sectional view of plowed ground in the illustration
above shows very much the same condition as shown
in the tube.
INFLUENCE OF WATER 19
In illustration C the water has reached the bottom of
the cloddy portion. The uneven edge shows that where
the soil particles are compact the water climbs upward,
thus illustrating an important characteristic of capil-
larity. Too many air spaces in the cloddy ground
break up the capillarity so that water will not climb as
rapidly or as effectively and abundantly as it does in
soil finely compacted. Two hours were required for
the water to rise from the bottom of the tube to the
Illustration D is the same tube photographed 22 hours
later. Observe that the soil is thoroughly permeated
with water up to the cloddy portion, that the moisture
in the cloddy part and the pulverized part above the
clods is very slight, and that on top no moisture is to be
discerned. This shows that moisture does not rise to
the surface of the ground any faster than it is evaporated.
If this tube contained a plant above the cloddy part it
would be plainly evident that the amount of moisture
the roots could secure would not be enough to promote
the healthy growth of the plant. Therefore, it is very
important that this cloddy condition does not exist at
the bottom of the seed bed as much on account of
moisture as heat and air.
Film water displays itself only upon the surface of the
soil grain. That is why it is called film water. It
forms a film around the grain. Anyone can easily
satisfy himself as to the truth of this, by taking a
marble and immersing it in a glass of water, then with-
drawing it. All the water required to form the film will
cling to the marble and the rest will drop off. Suppose
that marble is one inch in diameter. It will fill a cube
one inch square that is, six points on the surface of the
20 THE OLIVER PLOW BOOK
marble will touch six points of the cube and all the rest
of the space between the cube and the surface of the
marble is air space. The area of the surface of the
marble is found by multiplying the diameter squared by
3.1416, making 3.1416 square inches of film surface for
the water. This is the amount of the film surface dis-
A cube one inch square will hold 1 ,000 marbles one-
tenth of an inch in diameter. The square inch of surface
of each marble one-tenth of an inch in diameter is one
hundredth of what it is on the large marble, or .031416
of an inch. This multiplied by 1 ,000, the number of
marbles of this diameter required to fill the cube, makes
31.416 square inches of film surface, in contrast with the
3.1416 displayed in the one marble. Thus, if you take
the 1 ,000 marbles in the cube immersing them in water,
and withdrawing them as you would the large marble,
you would have 31.4+ square inches of surface holding
water, against 3.1+ square inches on the large marble.
This means that the air spaces have been diminished in
size and the water holding content of the soil increased,
proving that the finer the soil is broken up, the greater
water-holding capacity it has, consequently, the break-
ing of the soil into fine particles is necessary to improve
it for water holding content. For this reason the
ground should be well pulverized when plowing.
It is further evident, from the marble illustration, that
the size of the soil particles has everything to do with
the water holding content. As an illustration of the
capacities of different soils, for capillary attraction and
for holding water, samples of clay, clay loam, loam,
sandy loam, and loamy sand were placed in the tubes
under the names, small clods being placed on top of the
INFLUENCE OF WATER
Dipping a marble into a
glass of water as shown in
this illustration will con-
vince anyone that surplus
water will not cling to the
marble when it is removed.
Enough water should be
supplied in the soil so that