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Cannabis sativa L.
Syn.: Cannabis indica Lam.
Cannabaceae
Hemp, Marijuana, Cannabis oil
Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.
- Uses
- Folk Medicine
- Chemistry
- Toxicity
- Description
- Germplasm
- Distribution
- Ecology
- Cultivation
- Harvesting
- Yields and Economics
- Energy
- Biotic Factors
- References
A multiple-use plant, furnishing fiber, oil, medicine, and narcotics. Fibers
are best produced from male plants. In the temperate zone, oil is produced
from females which have been left to stand after the fiber-producing males have
been harvested. Leaves are added to soups in southeast Asia. Varnish is made
from the pressed seeds. Three types of narcotics are produced: hashish
(bhang), the dried leaves and flowers of male and female shoots; ganja, dried
unfertilized inflorescences of special female plants; and charas, the crude
resin, which is probably the strongest. Modern medicine uses cannabis in
glaucoma and alleviating the pains of cancer and chemotherapy. More resin is
produced in tropical than in temperate climates. Lewis lung adenocarcinonoma
growth has been retarded by oral administration of
delta-9-tetrahydrocannabinol, delta-8-tetrahydrocannabinol and cannabinol, but
not by cannabidiol. (J.N.C.I. 55: 597-602. 1975). The delta-9 also inhibits
the replication of Herpes simplex virus.
Medicinally, plants are tonic, intoxicant, stomachic, antispasmodic, analgesic,
narcotic, sedative and anodyne. Seeds and leaves are used to treat old cancer
and scirrhous tumors. The seed, either as a paste or as an unguent, is said to
be a folk remedy for tumors and cancerous ulcers. The decoction of the root is
said help remedy hard tumors and knots in the joints. The leaf, prepared in
various manners, is said to alleviate cancerous sores, scirrhous tumors, cold
tumors, and white tumors. The plant is also used for mammary tumors and corns
(C.S.I.R., 1948-1976). Europeans are said to use the dregs from
Cannabis pipes in "cancer cures" (Watt and Breyer-Brandwijk, 1962). Few
plants have a greater array of folk medicine uses: alcohol withdrawal, anthrax,
asthma, blood poisoning, bronchitis, burns, catarrh, childbirth, convulsions,
coughs, cystitis, delirium, depression, diarrhea, dysentery, dysmenorrhea,
epilepsy, fever, gonorrhea, gout, inflammation, insomnia, jaundice, lockjaw,
malaria, mania, mennorhagia, migraine, morphine withdrawal, neuralgia, palsy,
rheumatism, scalds, snakebite, swellings, tetany, toothache, uteral prolapse,
and whooping cough. Seeds ground and mixed with porridge given to weaning
children.
Most varieties contain cannabinol and cannabinin; Egyptian variety contains
cannabidine, cannabol and cannabinol, their biological activity being due to
the alcohols and phenolic compounds. Resin contains crystalline compound
cannin. Alcoholic extracts of American variety vary considerably in
physiological activity. Per 100 g, the seed is reported to contain 8.8 g H2O,
21.5 g protein, 30.4 g fat, 34.7 g total carbohydrate, 18.8 g fiber, and 4.6 g
ash. In Asia, per 100 g, the seed is reported to contain 421 calories, 13.6 g
H2O, 27.1 g protein, 25.6 g fat, 27.6 g total carbohydrate, 20.3 g fiber, 6.1 g
ash, 120 mg Ca, 970 mg P, 12.0 mg Fe, 5 mg beta-carotene equivalent, 0.32 mg
thiamine, 0.17 mg riboflavin, and 2.1 mg niacin. A crystalline globulin has
been isolated from defatted meal. It contains 3.8% glycocol, 3.6 alanine, 20.9
valine and leucine, 2.4 phenylalanine, 2.1 tyrosine, 0.3 serine, 0.2 cystine,
4.1 proline, 2.0 oxyproline, 4.5 aspartic acid, 18.7 glutamic acid, 14.4
tryptophane and arginine, 1.7 lysine, and 2.4% histidine. Oil from the seeds
contains 15% oleic, 70% linoleic, and 15% linolenic and isolinolenic acids.
The seed cake contains 10.8% water, 10.2% fat, 30.8% protein, 40.6% N-free
extract, and 7.7% ash (20.3% K2O; 0.8% Na2O; 23.6% CaO, 5.7% MgO, 1.0% Fe2O3,
36.5% P2O5, 0.2% SO3; 11.9% SiO2, 0.1% Cl and a trace of Mn2O3). Trigonelline
occurs in the seed. Cannabis also contains choline, eugenol, guaiacol,
nicotine, and piperidine (C.S.I.R., 1948-1976), all listed as toxins by the
National Institute of Occupational Safety and Health. A beta-resercyclic acid
derivative has antibiotic and sedative properties; with a murine LD56 of 500
mg/kg, it has some aritiviral effect and inhibits the growth of mouse mammary
tumor in egg embryo (Watt and Breyer-Brandwijk, 1962).
Non-users may suffer muscular incoordination (9 of 22 persons), dizziness (8),
difficulty concentrating (8), confusion (7), difficulty walking (7), dysarthria
(7), dry mouth (7), dysphagia (5), blurred vision (5), and vomiting (1),
following oral ingestion of THC disguised in cookies (MMWR, October 20, 1978).
People working with the plant or the fiber may develop dermatitis. In larger
doses, hemp drugs may induce catalepsy, followed by coma and DEATH from cardiac
failure (C.S.I.R., 1948-1976).
Annual herb, usually erect; stems variable, up to 5 m tall, with resinous
pubescence, angular, sometimes hollow, especially above the first pairs of true
leaves; basal leaves opposite, the upper leaves alternate, stipulate, long
petiolate, palmate, with 3-11, rarely single, lanceolate, serrate, acuminate
leaflets up to 10 cm long, 1.5 cm broad; flowers monoecious or dioecious, the
male in axillary and terminal panicles, apetalous, with 5 yellowish petals and
5 poricidal stamens; the female flowers germinate in the axils and terminally,
with one 1-ovulate ovary; fruit a brown, shining achene, variously marked or
plain, tightly embracing the seed with its fleshy endosperm and curved embryo.
Fl. summer; fr. late summer to early fall; year round in tropics.
Seeds weigh 1.5-2.5 gm/100 seeds.
As Cannabis sativa has been cultivated for over 4,500 years for
different purposes, many varieties and cultivars have been selected for
specific purposes, as fiber, oil or narcotics. Drug-producing selections grow
better and produce more drug in the tropics; oil and fiber producing plants
thrive better in the temperate and subtropical areas. Many of the cultivars
and varieties have been named as to the locality where it is grown mainly.
However, all so called varieties freely interbreed and produce various
combinations of the characters. The form of the plant and the yield of fiber
from it vary according to climate and particular variety. Varieties cultivated
particularly for their fibers have long stalks, branch very little, and yield
only small quantities of seed. Varieties which are grown for the oil from
their seed are short in height, mature early and produce large quantities of
seed. Varieties grown for the drugs are short, much-branched with smaller
dark-green leaves. Between these three main types of plants are numerous
varieties which differ from the main one in height, extent of branching and
other characteristics. Reported from the Central Asia, Hindustani, and
Eurosiberian Centers of Diversity, marijuana or cvs thereof is reported to
tolerate disease, drought, fungus, high pH, insects, laterite, low pH,
mycobacteria, poor soil, slope, and weeds. (2n = 20, 10, 40.)
Native to Central Asia, and long cultivated in Asia, Europe, and China. Now a
widespread tropical, temperate and subarctic cultivar and waif. The oldest use
of hemp seems to be for fiber, and later the seeds began to be used for
culinary purposes. Plants yielding the drug seem to have been discovered in
India, cultivated for medicinal purposes as early as 900 BC. In medieval times
it was brought to North Africa where today it is cultivated exclusively for
hashish or kif.
Plants very adaptable to soil and climatic conditions. Hemp for fiber requires
a mild temperate climate with at least 67 cm annual rainfall, with abundant
rain while seeds are germinating and until young plants become established.
Thrives on rich, fertile, neutral to slightly alkaline, well-drained silt or
clay loams with moisture retentive subsoils; does not grow well on acid, sandy
soils. Of the many types of hemp, some are adapted to most vegetated terrains
and climates. Ranging from Cool Temperate Steppe to Wet through Tropical Very
Dry to Wet Forest Life Zones, marijuana is reported to tolerate annual
precipitation of 3 to 40 dm (mean of 44 cases = 9.9 dm), annual temperature of
6 to 27°C (mean of 44 cases = 14.4), and pH of 4.5 to 8.2 (mean of 38 cases
6.5) (Duke, 1978, 1979).
Propagation mainly by seed. Experimentally, drug plants have been propagated
from cuttings but such plants do not come true as to drug content of parent.
Seeds stored in cool, dry place remain viable for up to two years. Hemp seed
sown as early in spring as possible. Before sowing, land is plowed (in fall)
several times to a depth of about 20-23 cm and repeatedly harrowed the land.
In spring the land is harrowed again and rolled, making a firm tilth over the
entire surface. In some areas a first plowing is done in the fall and red
clover or lupin planted; in January or February a second plowing turns these
under as a green-manure. Generally sown in March, seeds germinate at low
temperature, but not below 1deg.C. Rate of seed sown varies with type of fiber
desired; for coarse fiber for cordage and coarser textiles, 2.5 bu/ha is used;
for finest fibers, 7.5-10 bu/ha used. Seed sown by machine in rows from 12 cm
upwards, placing the seed at depth of 3.5 cm at rate of 40-60 kg/ha. In many
countries seed sown broadcast. When grown for seed (oil), seed sown by drills;
then such plants sometimes reach height of 5.3 m with thick stems up to 5 cm in
diameter, much-branched. For fiber, stems up to 2 m tall and 0.5 cm in
diameter are best; larger stems tend to get woody and have lower fiber content.
Besides, they are more difficult to handle during harvesting, retting and
scutching. Plants require little cultivation, except for weeding during early
stages of growth. Hemp grows rapidly and soon crowds out weeds. After plants
are 20 cm tall, weeding is abandoned. Hemp tends to exhaust the soil of
nutrients. Some nutrients are returned to the soil after plants are harvested.
On medium fertile soils a dressing of farm manure or a green-manure crop should
be added and turned under. Chalk, potash, or gypsum may be applied to the soil
to add the needed nutrition. Sodium nitrate and ammonium along with potassium
sulfate have a beneficial effect on the fiber crop. Fiber-producing plants
should always have plenty of proper nutrients, especially nitrogen, which is
the most important element needed. Irrigation is seldom practiced.
Hemp is ready for harvest four to five months after planting, rarely earlier
for some varieties. Harvesting depends on the climatic conditions, the variety
of hemp grown and whether the crop is being grown for hemp or seed. In
temperate areas, hemp is usually harvested from mid July to mid August. Both
male and female plants look alike until they flower; then the male plants turn
yellow and die, whereas the female plants remain dark green for another month
until the seed ripens. Male plants are ready to harvest for fiber when the
leaves change from dark green to light brown. The best yield of fiber (and
only male plants are used) is then obtained. Hemp is harvested when the
staminate flowers are beginning to open and shed their pollen. Seed is
harvested from the female plants when most of it falls off when the plant is
shaken. Best time of day to harvest seed is in early morning when fruits are
turgid and conditions damp. As fruits dry out by mid-day, seed loss increases
due to shattering. Usually stems are cut and the seeds shaken out over canvas
sheets or beaten with sticks to extract the seeds. For fiber, hemp plants are
cut by hand with a hemp knife, similar to a long-handled sickle. Plants are
cut 2-3 cm above the ground and spread on the ground to dry. In some areas,
the entire plants are pulled up and laid out to dry. Hand cutting, one man can
cut about one-fifth hectare per day. Sometimes specially designed harvesters
with a tractor are able to harvest four hectares a day. In many areas several
varieties of hemp are grown so as to spread out the harvest, one maturing in
late July and used later for seed crop in September, a second crop maturing in
mid August, and a third maturing near end of August. Fiber is extracted from
the stems of hemp by retting by methods similar to those used for other fiber
plants. Sometimes the stems are dried before they are retted. After plants
have air-dried for 4-6 days, the root and flower ends are cut off and the
remaining portions, with branches and leaves taken or beaten off, are made into
small bundles. For retting, 15-20 of these smaller bundles are made into
larger bundles. In other areas stalks are not dried before retting, green
stems, after roots and flower ends have been cut off, are made into bundles,
and retted immediately. Hemp can be water retted, dew retted, or snow retted,
according to the climatic conditions. The retted hemp stalks consist of fiber
in the outer rind and a woody interior portion. Fiber is separated from the
stalk by a breaking process. Stalks are dried after retting and the woody
shive is broken into short pieces called hurds. Eventually the fibers are
separated from the interior woody pieces by scutching by passing the bundles
through a number of fluted rollers and then past large revolving drums with
projecting bars which remove any remaining pieces of wood. Machines are able
to handle 3-3.5 MT dried straw every hour, producing 0.4-0.5 MT of cleaned
fiber.
Yields of hemp per hectare depend on climatic conditions, variety grown, soil
and nutrition, and spacing of plants in the field. Weight of dried stems per
hectare is usually between 4.5 to 7.5 T, with a yield of fiber about 25% of the
dried stalks. Usually the taller the plant, the longer will be the fiber with
a greater yield per plant. In some areas fiber yields of 850- 1,700 kg/ha
compared to 1,300-1,700 kg/ha seed and 30 kg ganja. The U.S.S.R. is the
largest producer of hemp in the world, producing about 33% of hemp fiber,
annually 105,000 MT compared to the world production of 255,000 MT (excepting
China). France and West Germany are the chief importers, Italy and Yugoslavia
exporters. Chile, China, Japan and Peru also produce hemp. Narcotic
production is usually clandestine, but there is legal marijuana production in
India. India is the main producer and exporter of oil from the seed.
In India, plants remaining in the field after harvesting for fiber are allowed
to set seed. They are cut after the fruits are ripened and dried and threshed
for seed collection. Grown solely for seeds, an average crop yields 1.3 to 1.6
MT/ha seed. The world low production yield was 288 kg/ha in Democratic
People's Republic of Korea, the international production yield was 613 kg/ha,
and the world high production yield was 3,842 kg/ha in People's Republic of
China.
Among diseases of Cannibis are: Botryosphaeria marconii (stem
canker, wilt), Botrytis cinerea (gray mold), Cylindrosporium sp.
(leaf spot), Fusarium sp. (canker, stem rot), Gibberella saubinetii
(stem rot), Hypomyces cancri (?root rot), Macrophominia phaseoli,
Phomopsis cannabina, Phymatotrichum omivorum (root rot), Sclerotinia
sclerotiorum (stem rot, wilt), Sclerotium rolfsii (southern blight),
Septoria cannabis (leaf spot). Nematodes include: Ditylenchus
dipsaci, Heterodera humuli, Longidorus maximus, Meloidogyne hapla, M.
incognita, M. incognita acrita, M. spp., and Pratylenchus coffeae
(Golden, p.c., 1984). Occasionally Orobanche ramosa is
paratitic on the roots.
- Duke, J.A. 1978. The quest for tolerant germplasm. p. 1-61. In: ASA Special
Symposium 32, Crop tolerance to suboptimal land conditions. Am. Soc. Agron.
Madison, WI.
-
Duke, J.A. 1979. Ecosystematic data on economic plants. Quart. J. Crude Drug
Res. 17(3-4):91-110.
-
C.S.I.R. (Council of Scientific and Industrial Research). 1948-1976. The wealth
of India. 11 vols. New Delhi.
-
Watt, J.M. and Breyer-Brandwijk, M.G. 1962. The medicinal and poisonous plants
of southern and eastern Africa. 2nd ed. E.&S. Livingstone, Ltd., Edinburgh
and London.
Complete list of references for Duke, Handbook of Energy Crops
Last update July 3, 1996