Hibiscus cannabinus L.
Kenaf, Bimli, Bimlipatum, Jute, Deccan hemp
Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.
- Folk Medicine
- Yields and Economics
- Biotic Factors
Kenaf is cultivated for its bast fibers which resemble and substitute for jute
fibers. Fiber strands, 1.53 m long, are used for rope, cordage, canvas,
sacking, carpet backing, and fishing nets. It is cultivated secondarily for
the seeds which contain about 20% oil, used for: salad, cooking, and lubricant
oils. Oil is also used in the manufacture of soap, linoleum, paints and
varnishes, and for illumination. In 1968, Florida used 600 ha growing kenaf
for bean poles (Whitely, 1981). Recently the pulp has been used in
paper-making. Leaves are used as a potherb. A concentrated food for cattle in
the form of seed-cake comes from the residue after oil extraction. Africans
use soot from the stems as a black pigment. They also use a piece of the stem
as a base for drilling fire.
Reported to be anodyne, aperitif, aphrodisiac, fattening, purgative, and
stomachic, kenaf is a folk remedy for bilious conditions, bruises, fever, and
puerperium (Duke and Wain, 1981). Powdered leaves are applied to Guinea worms
in Africa. Africans use peelings from the stems for anemia, fatigue,
lassitude, etc. In Gambia, the leaf infusion is used for coughs. Ayurvedics
use the leaves for dysentery and bilious, blood and throat disorders. Seeds
are applied externally to aches and bruises. Medicinally, juice of the flowers
with sugar and black pepper is used in biliousness with acidity. Seeds are
considered aphrodisiac and fattening.
Seeds contain radium, thorium, and rubidium, and a fatty oil like arachis oil
(Reed, 1976). Seeds also contain 9.6% moisture, 6.4% ash, 20.4% fatty oil,
21.4% nitrogenous matter, 15.7% saccharifiable matter, 12.9% crude fiber, and
13.9% other matter. The seed oil contains 45.3% oleic-, 23.4% linoleic- 14.0%
palmitic-, and 6.0% stearic-acids. Dry press cake contains 33.0% protein, 6.0%
oil, 17.4% crude fiber, 6.0% ash, and 37.6% N-free extract. The following
amino acids have been identified in the acid hydrolysates of the proteins
ALBUMIN (N, 15.38%) histidine, 2.57; arginine, 6.23; tyrosine, 1.80; lysine,
3.05; GLOBULIN-1 (N, 18.41%): histidine, 3.68; arginine, 13.60; tyrosine, 2.13;
lysine, 2.63; GLOBULIN-2: histidine, 3.24; arginine, 12.16; tyrosine, 2.04;
lysine, 1.95%. The cake, used as a fertilizer, contains: nitrogen, 5.25;
phosphoric acid (P2O5), 0.95; and potash (K2O), 3.74%. Coloring matter of the
flowers consists mostly of the glucoside cannabiscitrin (C21H20O13); with a
small amount of the aglucone, cannabiscetin (C15H10O8), a flavonol identical
with myricetin (C.S.I.R., 19481976). Fresh stems from India contain, (ZMB):
15.0% CP, 19.9% CF, 8.2% ash, 5.8% EE, 51.1% NFE, 2.08% Ca, and 0.5% P. Dried
leaves, eaten in various countries, contain 13.1% CP, 11.6% CF, 11.8% ash, 2.1%
EE, 61.4% NFE, 3.31% Ca, and 0.35% P (Gohl, 1981).
Woody to herbaceous annual, mostly unbranched, fast-growing, with prickly
stems, up to 4.2 m tall; leaves alternate, long-petiolate, shallowly to deeply
parted, with 37 toothed lobes; flowers solitary, large to 10 cm in diameter,
short-stalked, axillary, yellow with purple centers; sepals 5, petals 5;
stamens numerous, connate; ovary superior; fruit a many-seeded, hairy capsule
about 1 cm long; seeds brown, glabrous, wedge-shaped, 5 mm long, 3 mm wide,
weight 25g/1000. Root a deep-penetrating taproot with deep-seated laterals
Reported from the African and Hindustani Centers of Diversity, kenaf, or cvs
thereof is reported to tolerate laterites, low pH, and some waterlogging or
temporary inundations (Duke, 1978). Many cvs have been developed. Some are:
simplex, viridis, Tuber, purpureus, and vulgaris. All trial
crosses between the varieties have been successful. Diploid (2n = 36)
and tetraploid (2n = 72) races have been found. Both self- and
cross-pollination is found among the varieties (C.S.I.R., 19481976).
Probably native to Africa, East Indies, Asia, or Australia, now naturalized in
Africa and Asia, generally cultivated in India, and introduced in India,
Indochina, Taiwan, Indonesia, and North and South America. Its distribution is
between 45°N and 30°S.
Ranging from Warm Temperate Thorn to Moist through Tropical Very Dry to Wet
Forest Life Zones, kenaf is reported to tolerate annual precipitation of 5.7 to
41.0 dm (mean of 29 cases = 14.8), annual temperature of 11.1 to 27.5°C
(mean of 29 cases = 21.1), and pH of 4.3 to 8.2 (mean of 24 cases = 6.1) (Duke,
1978, 1979). Kenaf is often recommended for tropical and subtropical climates,
from sea-level to 1000 m altitude, with no night temperatures below 18.3°C,
and 500 to 600 cm rainfall over 45 months with wet and dry periods. It is
less exacting in its requirements than jute. It thrives best with temperatures
of 1527°C during the growing season. The plant is frost sensitive and
damaged by heavy rains with strong winds. Kenaf is adaptable to a variety of
soils, best being a deep, friable, well-drained, sandy loam with humus; light
sandy soils are not recommended. A pH of neutral to slightly acid is suggested
(C.S.I.R., 19481976). At higher latitudes the plant remains vegetative and
does not flower until the daylength is less than 12.5 hr/day. Two weeks of
very cloudy days will induce flowering as daylength approaches 12.5 hr.
Propagation is by seed. Seed retain viability for about 8 months under
ordinary storage conditions. Soil preparation should be deep (at least 20 cm)
and thorough. Seed is broadcast or planted with a grain drill in rows at the
beginning of the rainy season, with about 630 kg seed/ha drilled 15 cm by 15
cm on dry soils or 12.5 cm by 12.5 cm on wet soils. Often two seeds are
drilled and one seedling removed if germination has been good to insure an even
stand for the production of uniform stalks. Planting depth is about 0.53.2
cm. Weeding for the first month is important. North of the equator planting
is done in May or June, allowing as much time as possible for vegetative growth
before flower set. Soils may be treated with manure or green-manure.
Treatment with 585 kg/ha ammonium sulfate and green-manure of Mimosa
envisa increases the yield of kenaf by 50%. One fertilizer recommendation
is ca 3570 kg/ha N, 4060 kg/ha P2O5, and 4565 kg/ha K2O. A kenaf crop of 50
MT green plants/ha withdraws from the soil about 175 kg N, 15 kg P, 75 kg K,
105 kg Ca, and 30 kg Mn (Whitely 1981). Almost any farmer living between
45°N and 30°S latitude, with a soil cabable of producing corn, cotton,
sugar, beans, or vegetables can produce good crops of kenaf. Any of these
crops may be used in rotation with kenaf. Rotation with green-manure crops is
also recommended, as Crotalaria anagyroides, C. usaramoensis, or
Mimosa envisa, which may be plowed under (Reed, l976).
Highest quality fiber is obtained when plants are harvested during the
flowering period, usually in August north of the equator. Planting to harvest
is from 90125 days. Three reaping methods are used: hand-cut, machine-cut,
and pulled by roots, as the lower stem contains the best fibers. Hand-cutting
is practiced only where labor is cheap and plentiful. A water source is
necessary at harvest time since retting from 522 days is required to separate
the bark from the wood and release the fibers. The fibers are then cleaned by
hand and dried in the sun. A skilled worker can strip and wash about 3645 kg
dry clean fiber per day. Equipment essential for growing and harvesting kenaf
consists of a tractor, plow, harrow, light grain drill, and a decorticator. A
small farmer can generally make money with the smallest hand-fed decorticator
and 6 hectares. However, it is more profitable to plant a larger acreage and
use a semi-automatic decorticator. Farmers in Cuba and the United States avoid
expensive hand labor by utilizing a self-propelled harvester decorticator,
which will produce 45 kg of dried fiber per working hour (Reed, 1976).
Yields of fibers in stems varies from 27%, and primarily depends on the
fertility of the soil. Fiber yields in India are 9001800/ha; in Java, 450
kg/ha, and rarely to 900 kg/ha; in Cuba up to 2700 kg/ha. Trials of 6 cvs in
Tunisia gave fiber yields of 8803670 kg/ha (Jiranek, 1976). Whitely suggests
a preharvest cost of ca $300 per hectare to produce kenaf, with yields of 11
MT/ha indicating a per ton cost of $27, $19 at 16 MT/ha, and $15/MT at yields
of 2 MT/ha. During 1974, the price range of pulpwood delivered to the mills
was $3344/MT (Whitely, 1981). World production of kenaf is ca 1,300,000 MT
per year, mainly produced by Thailand, India, China, USSR, and East Pakistan.
The 19711972 estimate for Thailand is about 430,000 MT. The chief importers
are India, Japan, Belgium, France, Italy, West Germany, Spain, and United
Kingdom. Wholesale prices in Mar., Apr., and May 1970 were 160169 baht/picul
(Thailand measures), but prices shot upward in the first half of 1971. In
developing countries and Mainland China, the continued growth of bagged or
baled agricultural output makes it likely that jute-kenaf usage as sacking
materials will continue to grow (an increase of 50% over 1970 was projected for
1980). Seed yields can run ca 7002000 kg/ha (C.S.I.R., 19481976).
According to the phytomass files (Duke, 1981b), annual productivity ranges from
825 MT/ha. Maryland yields though are closer to 46 MT/ha (T.A. Campbell,
personal communication). Still there are kenaf advocates squared off against
the tree advocates. Whitely says, "Kenaf, under favorable conditions, may be
several times more productive than trees on a per acre basis... Kenaf dry
material could be produced at about half the cost per unit of producing
pulpwood." Australians are not quite so optimistic. Stewart et al. say, "The
most likely contribution of kenaf to a liquid fuels program would be if the
bark were processed to very high quality pulp using some of the core wood as
fuel, and the remainder of the core wood were used as a raw material for
production of methanol. The bark (40% of stem) has long fibers giving high
strength paper pulps. The other 60% (the core wood) is composed of short
fibers giving low quality pulp. As a feedstock for liquid fuel production,
kenaf yields only lignocellulose. Fuel production is likely to be less than
from sugarcane (Stewart et al, 1979). The cost of ethanol from wood using the
Rheinau process is estimated at $650 per MT, twice the estimated cost of
methanol from wood, based on CSIRO studies for the production of fermentable
sugar from kenaf in a plant sized to process 1250 MT wood per day, the amount
of kenaf expected from the Ord River region of Australia (comparable to several
Australian mills). According to Carlson et al. (1982), kenaf has yields nearly
5 MT/ha DM on abandoned strip mine soil treated with 112 MT/ha sludge. The
kenaf accumulated heavy metals. ICAR (1973) reports as much as 13.4 MT total
dry matter at Barrackpore, India, corresponding to an uptake of 100 kg N, 65 kg
P2O5, 165 kg K2O, 200 kg CaO, and 54 kg MgO.
Many fungi attack kenaf, a world survey being the following:
Acrostalagmus sp., Aecidium garckeanum, Alternaria diant hi, A.
gossypina, A. tenuis, Anthromocopsis sp., Ascochyta hibisci-cannabini,
Aspergillus glaucus, A. niger, Botrytis cinerea, Cephalotheca sp.,
Cercospora abelmoschi, C. abelmoschi-cannabini, C. hisbiscina, C. malayensis,
Cladosporium herbarum, Colletotrichum hibisci, C. hibisci-cannabini, C.
hibiscicola, Cytospora hibisci, Diplodia hibisci, Diplodina hibisci,
Echinobotrium atrum, Epicoccum neglectum, Fusarium culmorum, F. equiseti, F.
moniliforme, F. roseum, F. semitectum, F. vasinfectum, Glomerella cingulata,
Hyalothyridium nakatae, Illosporium hibisci, Leveillula malvacearum, L.
taurica, Macrophomina phaseoli, Macrosporium cladosporoides, M. hibiscinum,
Oospora lactis, Pellicularia filamentosa, Penicillium brevicaule, P.
crustaceum, P. glacum, P. luteum, Phoma labilis, P. sabdariffae, Phyllosticta
hibisci-cannabini, P. hibiscina, Phytophthora parasitica, Pythium parasitica,
P. perniciosum, Rhizopus nigricans, Sclerotinia fuckeliana, S. sclerotiorum,
Sclerotium rolfsii, Sclerotopsis hibisci, Spicaria elegans, Stysanus
stemonitis, Trichosphaeria sp., Vermicularia dematium. The
following bacteria are also known to attack kenaf: Agrobacterium tumefaciens
and Bacterium hibisci. The following have been isolated from kenaf:
Brazilian tobacco streak, Cotton leaf-curl, Groundnut rosette, Yellow vein
mosaic, and Anthocyanosis virus. Among nematodes infesting kenaf are:
Hemicycliophora penetrans, Helicotylenchus multicinctus, Meloidogyne arenaria,
M. hapla, M. incognita., M. incognita acrita, M. javanica, M. thamesi,
Pratylenchus brachyurus (Golden, p.c. 1984). The major insect pests are
Pink bollworm (Pectinophora gossypiella), Spiny bollworm (Earias
sp.), and Cotton aphid (Aphis gossypii) (Reed, 1976).
Complete list of references for Duke, Handbook of Energy Crops
- C.S.I.R. (Council of Scientific and Industrial Research). 19481976. The wealth
of India. 11 vols. New Delhi.
- Duke, J.A. 1978. The quest for tolerant germplasm. p. 161. In: ASA Special
Symposium 32, Crop tolerance to suboptimal land conditions. Am. Soc. Agron.
- Carlson, K.D., Cunningham, R.L., Garcia, W.J., Bagby, M.O., and Kwolek, W.F.
1982. Performance and trace metal content of crambe and kenaf grown on sewage
sludge treated stripmine land. Environmental Pollution A 29(2):145161
- Duke, J.A. 1979. Ecosystematic data on economic plants. Quart. J. Crude Drug
- Duke, J.A. 1981b. The gene revolution. Paper 1. p. 89150. In: Office of
Technology Assessment, Background papers for innovative biological technologies
for lesser developed countries. USGPO. Washington.
- Duke, J.A. and Wain, K.K. 1981. Medicinal plants of the world. Computer index
with more than 85,000 entries. 3 vols.
- Gohl, B. 1981. Tropical feeds. Feed information summaries and nutritive values.
FAO Animal Production and Health Series 12. FAO, Rome.
- ICAR. 1973. The Jute Agricultural Research Institute. Annual Report 1970.
- Jiranek, O. 1976. Prospects for kenaf (Hibiscus cannabinus) cultivation
in Tunisia. Agr. Trop. & Subtrop. 9:4955.
- Reed, C.F. 1976. Information summaries on 1000 economic plants. Typescripts
submitted to the USDA.
- Stewart, G.A., Gartside, G., Gifford, R.M., Nix, H.A., Rawlins, W.H.M., and
Siemon, J.R. 1979. The potential for liquid fuels from agriculture and forestry
in Australia. CSIRO. Alexander Bros., Mentone, Victoria, Australia.
- Whitely, E.L. 1981. Kenaf, Hibiscus cannabinus. p. 259268. In: McClure,
T.A. and Lipinsky, E.S. (eds.), CRC handbook of biosolar resources. vol. II.
Resource materials. CRC Press, Inc., Boca Raton, FL.
Last update Wednesday, January 7, 1998 by aw