manure, cowpeas, and clover can
most readily do their great work of improving the texture of the soil
and of making it fitter for plant growth.

[Illustration: FIG. 10. A TILE IN POSITION]

=Tile Drains.= Tile drains are the best and cheapest that can be used.
It would not be too strong to say that draining by tiles is the most
perfect drainage. Thousands of practical tests in this country have
proved the superiority of tile draining for the following reasons:

1. Good tile drains properly laid last for years and do not fill up.

2. They furnish the cheapest possible means of removing too much water
from the soil.

3. They are out of reach of all cultivating tools.

4. Surface water in filtering through the tiles leaves its nutritious
elements for plant growth.

=EXPERIMENTS=

=To show the Effect of Drainage.= Take two tomato cans and fill
both with the same kind of soil. Punch several holes in the bottom
of one to drain the soil above and to admit air circulation. Leave
the other unpunctured. Plant seeds of any kind in both cans and
keep in a warm place. Add every third day equal quantities of
water. Let seeds grow in both cans and observe the difference in
growth for two or three weeks.

=To show the Effect of Air in Soils.= Take two tomato cans; fill
one with soil that is loose and warm, and the other with wet clay
or muck from a swampy field. Plant a few seeds of the same kind in
each and observe how much better the dry, warm, open soil is for
growing farm crops.

SECTION VI. IMPROVING THE SOIL

We hear a great deal about the exhaustion or wearing out of the soil.
Many uncomfortable people are always declaring that our lands will no
longer produce profitable crops, and hence that farming will no longer
pay.

Now it is true, unfortunately, that much land has been robbed of its
fertility, and, because this is true, we should be most deeply
interested in everything that leads to the improvement of our soils.

When our country was first discovered and trees were growing everywhere,
we had virgin soils, or new soils that were rich and productive because
they were filled with vegetable matter and plant food. There are not
many virgin soils now because the trees have been cut from the best
lands, and these lands have been farmed so carelessly that the vegetable
matter and available plant food have been largely used up. Now that
fresh land