about two or
three feet apart. If the plants are set so that the plow and cultivator
can be run with the rows and also across the rows, they can be more
economically worked. Tobacco, like corn, requires shallow cultivation.
Of course the plants should be worked often enough to give clean culture
and to provide a soil mulch for saving moisture.

[Illustration: FIG. 191. TOPPING TOBACCO]

In tobacco culture it is necessary to pinch off the "buttons" and to cut
off the tops of the main stalk, else much nourishment that should go to
the leaves will be given to the seeds. The suckers must also be cut off
for the same reason.

The proper time for harvesting is not easily fixed; one becomes skillful
in this work only through experience in the field. Briefly, we may say
that tobacco is ready to be cut when the leaves on being held up to the
sun show a light or golden color, when they are sticky to the touch, and
when they break easily on being bent. Plants that are overripe are
inferior to those that are cut early.

The operations included in cutting, housing, drying, shipping, sweating,
and packing require skill and practice.

SECTION XXXVII. WHEAT

Wheat has been cultivated from earliest times. It was a chief crop in
Egypt and Palestine, and still holds its importance in the temperate
portions of Europe, Asia, Africa, Australia, and America.

[Illustration: FIG. 192. A HAND]

[Illustration: FIG. 193. WHEAT HEADS]

This crop ranks third in value in the United States. It grows in cool,
in temperate, and in warm climates, and in many kinds of soil. It does
best in clay loam, and worst in sandy soils. Clogged and water-soaked
land will not grow wheat with profit to the farmer; for this reason,
where good wheat-production is desired the soil must be well drained
and in good physical condition--that is, the soil must be open, crumbly,
and mellow.

Clay soils that are hard and lifeless can be made valuable for
wheat-production by covering the surface with manure, by good tillage,
and by a thorough system of crop-rotation. Cowpeas and other legumes
make a most valuable crop to precede wheat, for in growing they add
atmospheric nitrogen to the soil, and their roots loosen the root-bed,
thereby admitting a free circulation of air and adding humus to the
soil. Moreover, the legumes leave the soil with its grains fairly close
packed, and this is a help in wheat growing.

One may secure a good seed-bed after cotton and co