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.

[Ill.u.s.tration: FIG. 49.--SPADING-FORK AND SPADE.]

[Ill.u.s.tration: 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 gra.s.s 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 gra.s.s 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.

[Ill.u.s.tration: FIG. 51.--A SLIP-NOSE SHARE. _N_, A SLIP-NOSE.]