380. Miscellaneous fibers. ВЂ” Manila hemp, or abaca

(Musa textilis), in the same genus as the banana, is much

grown in the Philippine Islands for strong fiber out of

which rope hawsers or cables, and high-grade binder

twine are made. The plant requires abundant rainfall,

considerable warmth, and well-drained soils. The leaf-

sheaths of the plant furnish the fiber, which the natives

get by scraping off the pulp.

Sisal {Agave rigida), in the same genus as the century

plant, furnishes a fiber used for twine and for mixing with

manila fiber in cordage. The leaves are crushed by

machinery to loosen the hard strands. It is not very

useful in marine service because salt water markedly

decomposes it.

A number of other plants producing fibers are grown in

various parts of the world : jute in India ; maguey in

Mexico and Central America; istle in Mexico, New

Mexico, and Texas; and New Zealand hemp in New

Zealand.

MISCELLANEOUS CROPS

Many other plants are grown wherever and for what-

ever purpose man desires them. He cares not what family

342 The Prirwi'^es of Agronomy

they are in, nor what kind of plants they are, provided he

can make some use of them. The use may in some cases

be harmful, but this makes no difference; if he wants the

plant, he grows it as a crop.

• 381. Cabbage {Brassica oleracea), and kohlrabi {Braa-

sica oleroffea var. cauh-rapa) are used to some extent for

feeding in isolated districts. Kohlrabi, not widely grown

Fia. 84. — Cabbage as a field crop. Delaware.

in America, is an enlargement of the stem, while cabbage

heads are massed leaves. Kohlrabi is sown, thinned,

cultivated, harvested, stored, and fed in the same way as

rutabagas; in yield and feeding value it is also very

similar to the rutabaga. Cabbages are commonly sown

in hot houses and transplanted in May or June two or

three feet apart in hills with rows equally far apart.

For feeding, the crops may be seeded thick in fields after

Fibers and Miscellaneous Crcrps 343

the last frost and thinned later. Their chief use is for

human food, though in some sections, they are grown

for stock-feed, yielding occasionally as high as forty

tons of forage to the acre. Cabbage is valuable for milch

cows, but is rather diflScult to cure; as pasturage it

serves both cattle and sheep very well. A cabbage field

is shown in Fig. 84.

382. Rape (Brassica Najms) grows from two to four

feet tall sending out many broad, succulent leaves in

early growth. Sown broadcast at the rate of three to

five pounds an acre, it will keep down weeds; it yields

most in rows two to three feet apart. It may be sown

in late spring or during early summer either alone or with

grain. Sometimes it is planted two or three weeks after

grain, leafing out abundantly when the grain is cut.

Sometimes it is sown between corn rows after cultivation

has ceased. It is valuable for hog or sheep pasture, but

is not cured for dry forage. Yields are rather heavy.

Dwarf Essex is the usual variety.

383. Kale (Brassica oleracea), a headless cabbage,

furnishes considerable winter soiling in the coast region

of Washington and Oregon, being cut for green feed

during the mild winter. The yields vary from ten to

thirty tons of green forage an acre, with fifteen to twenty

tons common under favorable conditions. This slightly

exceeds the yield of rape. Since all the mustards feed

heavily on mineral food of the soil, fertilizer is beneficial

in considerable quantities. Farm manure in the West

and commercial fertilizers in the East and in the Old

World are used to supply these demands.

384. Enemies. — Although intensive culture should

easily control the weeds, some insects and the disease

club-root, common to the whole family, are by no means

easily eradicated. The club-root {Plasmodiorpha bra^ssi-

344 The Principles of Agronomy

ccb) fungus develops inside the root, distorting it and

causing the plants to die. The spores live in the soil

awaiting a chance to attack other roots. Long rotation

is the only method of control known for soil once infested.

The cabbage-root maggot {Pegomyia hrassicoB) lays

its eggs near the root, and the maggot riddles the root

causing the plants to look sickly and then to die. One

method of control is to place a spoonful of carbon

bisulfide in the soil four to six inches from the plant, and

to compress the soil tightly over hole. The liquid be-

comes gas and penetrates to the maggots.

Paris green or arsenate of lead, used as for potato bugs,

that is, sprayed on young plants, aids greatly in control-

ling the green cabbage worm (Pieris rapoe). Plowing as

soon as the crop is removed also helps considerably.

The cabbage aphis {Aphis brassicos) feeds on the leaves

and but for parasitic enemies would be decidedly injuri-

ous to all crucifers. It is best handled by thorough

spraying with tobacco solution (" black-leaf 40 '0 one

part in four hundred of water.

Flea-beetles, cabbage loopers, cabbage webworms,

cross-striped cabbage worms, diamond-back moths, and

cabbage curculios do damage in various ways. The

method of control is largely one of prevention by means

of culture and rotation. Any good manual gives insecti-

cide treatments.

TOBACCO {Nicotiana Tahacum)

Some plants have always supplied man with drugs

which he has chosen to use for remedies, stimulants, or

narcotics. Opium and cocaine were used for a long time

to. soothe, stimulate, or deaden nervous response. After

the discovery of America, tobacco became the chief

Fibers and MisceUaneous Crops 345

sedative plant, and it has gradually come into use the

world over. ' People smoke or chew it, or use it for snuff.

It finds some use as an insecticide and germicide, but this

is of minor importance compared to its use in satisfying

the "tobacco habit." The alkaloid poison nicotine is

responsible for its narcotic effect on the nervous system.

385. Distribution. — Extreme sensitiveness to soil con-

ditions limits the production of tobacco to small areas.

Each of the several types thrives only on a certain kind

of soil. Isolated districts from Connecticut to Texas

produce tobacco, but more than half of the crop of the

United States is grown in Kentucky, Virginia, and North

Carolina.

386. Culture. — Virgin soil or sod land is most favor-

able for tobacco cultivation. Even on these, however,

the plants are transplanted from seed-beds, which are

necessary on account of the extreme smallness of the seed.

The soil for the seed-bed is thoroughly fined and usually

sterilized to a depth of three or four inches by burning

brush or logs on it. Weed seeds are thus killed. In

March or April, the seed is broadcasted crosswise and

lengthwise of the seed plot to insure* even distribution.

When the plants are nine or ten weeks old, they are

transplanted from, one to three feet apart in rows two to

four feet apart. Frequent cultivation keeps down weeds

and at the same time mulches the soil. During growth,

the upright stem and upper leaves are cut off to stimulate

growth of the remaining leaves. Both field and shade

culture are practiced. Shading consists of a framework

over which is placed thin cotton or laths short distances

apart. These shut out a part of the light, thereby causing

the leaves to be thin and soft.

387. Curing and marketing. The leaves are either

pulled separately as they ripen or harvested all at once

346 The Prineiplea qf Agronomy

by cutting the whole plant. Curing requires steady dry-

ing that keeps the leaves pliable. Large barns are filled

with the leaves hung over laths. Slow fires are often

used to hasten curing in wet weather.

When well cured, the leaves are uniformly brown and

not brittle. On a damp day, they are stripped off the

stem and tied in bundles. These are later made into

larger bundles and allowed to " sweat." If warehouses

are near, the loose bundles are sold, but if shipping b

necessary, the tobacco is packed in lai^e hogsheads.

Since carefully^raded leaves bring the best price, con-

siderable care is exercised to separate leaves of different

quality and to place only one grade in a package.

388. Sugar-cane. — About half the sugar of the world

is made from sugar-cane (Sacckarum offidnarum), which is

produced only in tropical and semi-tropical countries.

Sia. 86. — Plantms BU|[ar-caae. Louisiana.

Fibers arid Miscellaneous Crops 347

British India, Cuba, Java, and Hawaii are the chief pro-

ducers. Louisiana and Texas produce all that is grown in

the United States. Alluvial soils along the lower Mis^-

sissippi supply abundant moisture and, therefore, pro-

duce good yields.

Sugar-cane, which is a perennial, has plume-like tassels,

bears no ears, has buds at the nodes, and resembles com

in size, nature of stem, leaves, and root-system. The

buds grow when the stalks are covered with moist

earth, as they are when a new crop is started (Fig 85).

After planting, sufficient cultivation is given to control

weeds.

Chemical analyses indicate the time for harvest by

showing when the sugar content is highest. The cane is

stripped of its leaves, topped in the field, and dit close

to the ground with large knives. Since the sugar content

lowers soon after: cutting, the cane is taken at once to the

factory, usually on cars. Heavy rolls crush the stalks,

squeezing out the juice, which is made into sugar by much

the same methods as beet juice.