or; 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 poo