e is as follows: for the first year, corn heavily
fertilized with stable manure; for the second year, sugar-beets; for the
third year, oats or barley; for the fourth year, clover; then go back
again to corn. In addition to keeping the soil fertile, there are two
gains from this rotation: first, the clean cultivation of the corn crop
just ahead of the beets destroys many of the weed seeds; second, the
beets must be protected from too much nitrogen in the soil, for an
excess of nitrogen makes a beet too large to be rich in sugar. The
manure, heavily applied to the corn, will leave enough nitrogen and
other plant food in the soil to make a good crop of beets and avoid any
danger of an excess.

When the outside leaves of the beet take on a yellow tinge and drop to
the ground, the beets are ripe. The mature beets are richer in sugar
than the immature, therefore they should not be harvested too soon. They
may remain in the ground without injury for some time after they are
ripe. Cold weather does not injure the roots unless it is accompanied by
freezing and thawing.

[Illustration: FIG. 212. SUGAR-BEETS ON THE WAY TO A FACTORY]

The beets are harvested by sugar-beet pullers or by hand. If the roots
are to be gathered by hand they are usually loosened by plowing on each
side of them. If the roots are stored they should be put in long, narrow
piles and covered with straw and earth to protect them from frost. A
ventilator placed at the top of the pile will enable the heat and
moisture to escape. If the beets get too warm they will ferment and some
of their sugar will be lost.

=Sugar-Cane.= Sugar-cane is grown along the Gulf of Mexico and the South
Atlantic coast. In Mississippi, in Alabama, Florida, Georgia, South
Carolina, northern Louisiana, and in northern Texas it is generally made
into sirup. In southern Louisiana and southern Texas the cane is usually
crushed for sugar or for molasses.

[Illustration: FIG. 213. STALK OF SUGAR-CANE
_A-B_, joints of cane showing roots; _B-C_, stem; _C-D_, leaves]

The sugar-cane is a huge grass. The stalk, which is round, is from one
to two inches in thickness.

The stalks vary in color. Some are white, some yellow, some green, some
red, some purple, and some black, while others are a mixture of two or
three of these colors. As shown in Fig. 214 the stalk has joints at
distances of from two to six inches. These joints are called nodes, and
the sections between the nodes are known