SPADING AND PLOWING
We have learned the important conditions necessary for the sprouting
of seeds and for the growth and development of roots. We have also
learned something about the soil, its properties, and its relation to,
or its behavior toward these important conditions. We are therefore
prepared to discuss intelligently methods of treating the soil to
bring about, or maintain, these conditions.
SPADING THE SOIL
The typical tool for preparing the soil for root growth is a spade or
spading fork (Fig. 49). With this tool properly used we can prepare
the soil for a crop better than with any other.
In spading, the spade or fork should be pushed into the soil with the
foot the full length of the blade and nearly straight down. The handle
is then pulled back and the spadeful of earth is pried loose, lifted
slightly, thrown a little forward, and at the same time turned. The
lumps are then broken by striking them with the blade or teeth of the
tool. All weeds and trash should be covered during the operation. A
common fault of beginners is to put the spade in the soil on a slant
and only about half the length of the blade, and then flop the soil
over in the hole from which it came, often covering the edge of the
unspaded soil. The good spader works from side to side across his
piece of ground, keeping a narrow trench or furrow between the spaded
and unspaded soil, into which weeds and trash and manure may be drawn
and thoroughly covered, and also to prevent covering the unspaded
soil. If this work has been well done with the ordinary spade or fork
and finished with a rake, the result will be a bed of soil twelve to
fifteen inches deep, fine and mellow and well prepared for root
penetration, for good ventilation, for the absorbing and holding of
moisture and warmth.
This method should always be employed for small gardens and flower
beds.
PLOWING
For preparing large areas of soil the plow is the tool most generally
used.
WHY DO WE SPADE AND PLOW?
To break and pulverize the soil and make it soft and mellow, so the
roots of plants may enter it in search of food, and get a firm hold
for the support of the plant which is above ground.
To make the soil open and porous, so that it can more readily absorb
rain as it falls on the surface.
To check loss of water by evaporation.
To admit air to the roots of plants. Also to allow air to act
chemically on the mineral and organic matter of the soil and make them
available to the crop.
To raise the temperature of soils in the spring, or of damp soils at
any time.
To mix manures and organic matter with the soil. The more thoroughly
manure is distributed through the soil the more easily plants will get
it and the greater will be its effect on the soil.
To destroy the insect enemies of the plant by turning them up to the
frost and the birds.
To kill weeds. Weeds injure crops:
They waste valuable moisture by pumping it up from the soil and
sending it out into the air through their leaves. In this way they do
their greatest injury to crops.
They crowd and shade the crop.
They take plant food which the plant should have.
Spading and plowing bring about conditions necessary for the sprouting
or germination of seeds.
Spading and plowing also tend to bring about conditions necessary for
the very important work of certain of the soil bacteria.
PARTS OF A PLOW
It will be found that a good farm plow has the following parts (Fig.
50):
_A standard_ or stock, the central part of the plow to which many of
the other parts are attached.
[Illustration: FIG. 49.--SPADING-FORK AND SPADE.]
[Illustration: FIG. 50.--A WOOD BEAM-PLOW
_a_, stock; _b_, beam; _c_, handles; _d_, clevis, _e_, shackle, _f_,
share; _g_, mould board; _h_, landside; _k_, jointer or skimmer, _l_,
truck or wheel, _p_, point or nose, _s_, shin.]
_A beam_, to which the power is attached by which the plow is drawn.
Some plows have wooden beams and others have iron beams.
_Handles_ by which the plowman guides and steadies the plow and also
turns it at the corners of the plowed ground in going about the field.
_A clevis_, which is attached to the end of the beam and is used to
regulate the depth of plowing. To the clevis is attached a _draft
ring_ or _shackle_, to which the horse or team is fastened. To make
the plow run deep the draft ring or shackle is placed in the upper
holes or notches of the clevis; to make it run shallow the ring is
placed in the lower holes. On some plows there are only notches in the
clevis for holding the ring, they answer the same purpose as holes.
The clevis is also used on some plows to regulate the width of the
furrow. By moving the draft ring or shackle towards the plowed land
the plow is made to cut a wider furrow, moving it away from the plowed
land causes the plow to cut narrower.
Some plows have a double clevis so that the draft ring may be raised
or lowered, or moved to right or left. With some plows the width of
the furrow is adjusted by moving the beam at its attachment to the
handles.
_A share_, called by some the point, which shears the bottom of the
furrow slice from the land. The share should be sharp, especially for
plowing in grass land and land full of tough roots. If the share,
particularly the point, becomes worn so that it bevels from beneath
upwards it will be hard to keep the plow in the soil, for it will tend
to slide up to the surface. If this happens the share must be renewed
or sharpened. Plows are being made now with share and point separate,
and both of these reversible (Fig. 51), so that if either becomes worn
on the under side it can be taken out and turned over and put back and
it is all right, they thus become self-sharpening.
_A mouldboard._ This turns and breaks the furrow slice. The degree to
which the mouldboard pulverizes depends on the steepness of its slant
upward and the abruptness of its curve sidewise. The steeper it is and
the more abrupt the curve, the greater is its pulverizing power. A
steep, abrupt mouldboard is adapted to light soils and to the heavier
soils when they are comparatively dry. This kind of a plow is apt to
puddle a clay soil if it is quite moist. For breaking new land a plow
with a long, gradually sloping share and mouldboard is used.
_A landslide_, which keeps the plow in place.
_A coulter._ Some plows have a straight knife-like coulter (Fig. 52)
which is fastened to the beam just in front of the mouldboard and
serves to cut the furrow slice from the land. In some plows this is
replaced by an upward projection of the share; this is wide at the
back and sharp in front and is called the shin of the plow from its
resemblance to the shin bone. The coulter is sometimes made in the
form of a sharp, revolving disk (Fig. 53), called a rolling coulter.
This form is very useful in sod ground and in turning under vines and
tall weeds. It also lessens the draft of the plow.
_A jointer_ or skimmer which skims stubble and grass from the surface
of the soil and throws them into the bottom of the furrow where they
are completely covered. The jointer helps also to pulverize the soil.
_A truck_ or wheel, attached under the end of the beam. This truck
makes the plow run steadier. This is sometimes used to make the plow
run shallower by setting it low down. This is not right, for it then
acts as a brake and makes the plow draw harder. The depth of the
furrow should be adjusted at the clevis.
A plow not only has parts but it has character also.
CHARACTERISTICS OF A GOOD PLOW
A good plow should be strong in build and light in weight.
The draft should be as light as possible.
The plow should run steadily.
A good plow should not only turn the soil but should pulverize it as
well.
When plowing, the team should be hitched to the plow with as short
traces as possible, and the plow should be so adjusted that it will
cut furrows of the required width and thickness with the least
possible draft on the team and the least exertion on the part of the
plowman.
THE FURROW SLICE
In plowing, the furrow slice may be cut thin and wide and be turned
over flat. This method is adapted to breaking new land and heavy sod
land.
It may be cut thick and narrow and be turned up on edge.
Or it may be cut of such a width and depth that the plow will turn it
at an angle of about forty-five degrees. By this last method the
greatest amount of soil can be turned at least expense of labor; the
furrow slice can be more thoroughly broken; the greatest surface is
exposed to the action of the air, and plant food is more evenly
distributed through the soil.
HOW DEEP SHALL WE PLOW?
We learned in a previous chapter that the roots of farm plants develop
largely in that part of the soil which is worked by the plow;
therefore, to have as much tilled soil as possible for root growth, we
should generally plow as deep as possible without turning too much of
the subsoil to the surface. Lands that have been plowed deep should be
deepened gradually by plowing up a half-inch to an inch of subsoil
each year until the plow reaches a depth of at least nine or ten
inches.
There is an opinion among many farmers that sandy soils should not be
plowed deep. But as these soils are apt to be leachy it seems best to
fill them with organic matter to as great a depth as possible to
increase their water-holding power, and this can best be done by
plowing farm manures in deep.
[Illustration: FIG. 51.--A SLIP-NOSE SHARE. _N_, A SLIP-NOSE.]
[Illustration: FIG. 52.--_C_, STRAIGHT KNIFE COULTER.]
[Illustration: FIG. 53.
An iron beam-plow, with rolling coulter and double clevis.]
[Illustration: FIG. 54.--A ROLLING COULTER HARROW.]
[Illustration: FIG. 55.--SPRING-TOOTHED HARROWS.]
In many parts of the South the farmers use very small plows and small
animals to draw them. The result is that the soil is not prepared to a
sufficient depth to allow of the large root development necessary for
large crops. These farmers need larger tools and heavier animals if
they expect to make much improvement in the yield of their crops.
These small plows and this shallow plowing have done much to aid the
washing and gulleying of the hill farms by rain. The shallow layer of
loose soil takes in the rain readily, but as the harder soil beneath
does not take the water as readily, the shallow plowed soil soon
fills, then becomes mud, and the whole mass goes down the slope. The
land would wash less if it had not been plowed at all, and least of
all if it were plowed deep, for then there would be a deep reservoir
of loose soil which would be able to hold a large amount of water
until the harder lower soil could take care of it.
BREAKING OUT THE MIDDLES
Some farmers have a way when getting the land ready for a crop, of
plowing the rows first and then "breaking out the middles" or spaces
between after the crop is planted. This is a poor practice, as it
interferes with thorough preparation of the soil. The ground can be
more thoroughly plowed and broken up before the crop is planted than
afterwards. This practice of leaving the middles interferes with
proper harrowing and after-cultivation.
THROWING THE LAND UP IN RIDGES
Many farmers throw the land up into ridges with the plow and then
plant on the ridge. When land is thrown into ridges a greater amount
of surface is exposed to the air and a greater loss of moisture by
evaporation takes place, therefore ridge culture is more wasteful of
soil water than level culture. For this reason dry soils everywhere
and most soils in dry climates should, wherever practicable, be left
flat. On stiff, heavy soils which are slow to dry out, and on low
bottom lands it may be desirable to ridge the land to get the soil
dried out and warmed quicker in the spring. Late fall and early
planter truck crops are often planted on the southern slopes of low
ridges thrown up with the plow for warmth and protection from cold
winds.
TIME TO PLOW
The time of plowing will depend somewhat on the nature of the soil,
climate and the crop.
More plowing is done in the spring just before planting spring and
summer crops than at any other time, excepting in localities that
plant large areas of winter grain and truck. This spring plowing
should be done early, for the spring plowing tends to dry the loosened
soil somewhat and allows it to become warm at an earlier date, and at
the same time the loosened soil tends to hold water in the lower soil
for future use by the crop and allows the soil to take in spring rains
more readily. If a cover crop or green manure crop is to be turned
under in the spring it should be done early so as to prevent the crop
to be turned under from pumping too much water out of the soil and
thus interfering with the growth of the crop for which the land is
being prepared.
There are some particular advantages to be gained by fall plowing in
heavy soils:
Immediately after harvest the land is usually dry and easy to work.
The soil plowed at this time and left rough is acted upon physically
by frost which pulverizes it, and chemically by rain and air which
renders plant food available.
Insects are turned up and exposed to frost and birds.
A great number of weeds are destroyed and the land is more easily
fitted for crops in the spring. Fall plowing should be done as early
as possible, especially in the dryer regions, to catch all water
possible. It is not advisable to plow sandy soils in the fall lest
plant food be washed out of them.
When possible a cover crop should be put on fall plowed land where
there is likely to be loss of plant food by leaching.
BARE FALLOW
The term "fallowing" is sometimes applied to the operation of plowing,
and sometimes the land is left bare without a crop sometime after
plowing; this is called "bare fallowing" the land.
Bare fallowing should not be practiced on all soils. It is adapted:
To dry climates and dry seasons where it is desirable to catch and
save every possible drop of rainfall, and where plant food will not be
washed out of the exposed soils by rains.
To heavy clay lands.
To lands that are foul with weeds and insects.
To sour soils which are sweetened by exposure to air and rain.
Light sandy soils should not be subjected to bare fallow unless they
are very foul with weeds. They should always be covered with a crop to
prevent loss of plant food by leaching.