-------------
FIRST YEAR || SECOND YEAR || THIRD YEAR
----------+----------++-----------+----------++-----------+----------
Summer | Winter || Summer | Winter || Summer | Winter
----------+----------++-----------+----------++-----------+----------
Corn | Crimson || Cotton | Wheat || Cowpeas | Rye for
| clover || | || | pasture
----------+----------++-----------+----------++-----------+----------

or

----------+----------++-----------+----------++-----------+----------
Summer | Winter || Summer | Winter || Summer | Winter
----------+----------++-----------+----------++-----------+----------
Corn | Wheat || Clover | Clover || Grass | Grass for
| || and grass | and grass|| |pasture or
| || | || | meadow
----------+----------++-----------+----------++-----------+----------
----------+----------++-----------+----------++-----------+----------

In these rotations the cowpeas and clovers are nitrogen-gathering crops.
They not only furnish hay but they enrich the soil. The wheat, corn, and
cotton are money crops, but in addition they are cultivated crops; hence
they improve the physical condition of the soil and give opportunity to
kill weeds. The grasses and clovers are of course used for pasturage and
hay. This is only a suggested rotation. Work out one that will meet your
home need.

=EXERCISE=

Let the pupils each present a system of rotation that includes the
crops raised at home. The system presented should as nearly as
possible meet the following requirements:

1. Legumes for gathering nitrogen.
2. Money crops for cash income.
3. Cultivated crops for tillage and weed-destruction.
4. Food crops for feeding live stock.

CHAPTER III

THE PLANT

SECTION XII. HOW A PLANT FEEDS FROM THE AIR

If you partly burn a match you will see that it becomes black. This
black substance into which the match changes is called _carbon_. Examine
a fresh stick of charcoal, which is, as you no doubt know, burnt wood.
You see in the charcoal every fiber that you saw in the wood itself.
This means that every part of the plant contains carbon. How important,
then, is this substance to the plant!

You will be surprised to know that the total amou