From the Handbook
of Energy Crops (unpublished)
by James A. Duke of Purdue University, Center for New Crops &
Names: Coconut, Narel
Yields and Economics
of Biomass Fuels
Coconut is one of the ten most useful trees in
providing food for millions of people, especially in the tropics. At
any one time a coconut palm has 12 different crops of nuts on it, from
opening flower to ripe nut. At the top of the tree is the growing
point, a bundle of tightly packed, yellow-white, cabbage-like leaves,
which, if damaged, causes entire tree to die, but if tree can be
spared, this heart makes a tasty treat, a 'millionaire's salad'.
flowers are protected by sheath, often used to fashion shoes, caps,
even a kind of pressed helmet for soldiers. Opened flowers provide a
good honey for bees. A clump of unopened flowers may be bound tightly
together, bent over and its tip bruised. Soon it begins to 'weep' a
steady dripping of sweet juice, up to a gallon per day. It contains
16-30 mg ascorbic acid/100 g. The cloudy brown liquid is easily boiled
down to syrup, called coconut molasses, then crystalized into a righ
dark sugar, almost exactly like maple sugar. Sometimes it is mixed with
grated coconut for candy. Left standing, it ferments quickly into a
beer with alcohol content up to 8%, called 'toddy' in India and Sri
Lanka; 'tuba' in Philippines and Mexico; and 'tuwak' in Indonesia.
After a few weeks, it becomes a vinegar. 'Arrack' is the product after
distilling fermented 'toddy' and is a common spirituous liquor consumed
in the East.
Nut has a husk, which is a mass of packed fibers called
coir, which can be woven into strong twine or rope, and is used for
padding mattresses, upholstery and life-preservers. Fiber resistant to
sea water and is used for cables and rigging on ships, for making mats,
rugs, bags, brooms, brushes, and olive oil filters in Italy and Greece;
also used for fires and mosquito smudges. If nut is allowed to
germinate, cavity fills with a spongy mass called 'bread' which is
eaten raw or toasted in shell over fire. Sprouting seeds may be eaten
Shell is hard and fine-grained, and may be carved into
all kinds of objects, as drinking cups, dippers, scoops, smoking pipe
bowls, and collecting cups for rubber latex. Charcoal used for cooking
fires, air filters, in gas masks, submarines, and cigarette tips.
Shells burned as fuel for copra kilns or housefires. Coconut shell
flour used in industry as filler in plastics. Coconut water is produced
by a 5 month old nut, about 2 cups of crystal clear, cool sweet (invert
sugars and sucrose) liquid, so pure and sterile that during World War
II, it was used in emergencies instead of sterile glucose solution, and
put directly into a patient's veins. Also contains growth substances,
minerals, and vitamins. Boiled toddy, known as jaggery, with lime makes
a good cement.
Nutmeat of immature coconuts is like a custard in
flavor and consistency, and is eaten or scraped and squeezed through
cloth to yield a 'cream' or 'milk' used on various foods. Cooked with
rice to make Panama's famous 'arroz con coco'; also cooked with taro
leaves or game, and used in coffee as cream.
Dried, desiccated, and
shredded it is used in cakes, pies, candies, and in curries and sweets.
When nuts are cut open and dried, meat becomes copra, which is
processed for oil, rich in glycerine and used to make soaps, shampoos,
shaving creams, toothpaste lotions, lubricants, hydraulic fluid,
paints, synthetic rubber, plastics, margarine, and in ice cream. In
India, the Hindus make a vegetarian butter called 'ghee' from coconut
oil; also used in infant formulas. When copra is heated, the clear oil
separates out easily, and is made this way for home use in producing
countries. Used in lamps. Cake residue used as cattle fodder, as it is
rich in proteins and sugar; should not give more than 4-5
lbs/animal/day, as butter from milk will have a tallow flavor. As cake
is deficient in calcium, it should be fed together with calcium rich
Trunk wood used for building sheds and other semi-permanent
buildings. Outer wood is close-grained, hard, and heavy, and when well
seasoned, has an attractive dark colored grain adaptable for carving,
especially ornamentals under the name of 'porcupine wood'. Coconut logs
should not be used for fences, as decayed wood makes favorable breeding
places for beetles. Logs are used to make rafts.
Sections of stem,
after scooping out pith, are used as flumes or gutters for carrying
water. Pith of stem contains starch which may be extracted and used as
Pitch from top of tree is sometimes pickled in coconut
vinegar. Coconut leaves made into thin strips are woven into clothing,
furnishings, screens, and walls of temporary buildings. Stiff midribs
make cooking skewers, arrows, brooms, brushes, and for fish traps.
fiber used in India to make mats, slippers, and bags. Used to make
short-lived torches. Coconut roots provide a dye, a mouthwash, a
medicine for dysentery, and frayed out make toothburshes; scorched,
used as coffee substitute. Believed to be antiblenorrhagic,
antibronchitis, febrifugal, and antigingivitic.
Coconut palm is
useful as an ornamental; its only drawback being the heavy nuts which
may cause injury to man, beast, or rooftop when they hit in falling
to Hartwell (1967-1971) coconuts are used in folk remedies for tumors.
Reported to be anthelmintic, antidotal, antiseptic, aperient,
aphrodisiac, astringent, bactericidal, depurative, diuretic, hemostat,
pediculicide, purgative, refrigerant, stomachic, styptic, suppurative,
and vermifuge, coconut, somewhere or other, is a folk remedy for
abscesses, alopecia, amenorrhea, asthma, blenorrhagia, bronchitis,
bruises, burns, cachexia, calculus, colds, constipation, cough,
debility, dropsy, dysentery, dysmenorrhea, earache, erysipelas, fever,
flu, gingivitis, gonorrhea, hematemesis, hemoptysis, jaundice,
menorrhagia, nausea, phthisis, pregnancy, rash, scabies, scurvy,
sorethroat, stomach, swelling, syphylis, toothache, tuberculosis,
tumors, typhoid, venereal diseases, and wounds (Duke and Wain, 1981).
100 g, the kernel is reported to contain 36.3 g H2O 4.5 g protein, 41.6
g fat, 13.0 g total carbohydrate, 3.6 g fiber, 1.0 g ash, 10 mg Ca, 24
mg P, 1.7 mg Fe, and traces of beta-carotene (C.S.I.R., 1948-1976). Per
100 g, the green nut is reported to contain 77-200 calories, 68.0-84.0
g H2O, 1.4- 2.0 g protein, 1.9-17.4 g fat, 4.0-11.7 g total
carbohydrate, 0.4-3.7 g fiber, 0.7-0.9 g ash, 11-42 mg Ca, 42-56 mg P,
1.0-1.1 mg Fe, 257 mg K, trace of beta-carotene, 0.4-0.5 mg thiamine,
0.03 mg riboflavin, 0.8 mg niacin, and 6-7 mg ascorbic acid (Food
Coconut oil is one of the least variable among
vegetable fats, i.e. 0.2-0.5% caproic-, 5.4-9.5 caprylic-, 4.5-9.7
capric-, 44.1-51.3 lauric-, 13.1-18.5 myristic, 7.5-10.5 palmitic-,
1.0-3.2 stearic-, 0-1.5 arachidic-, 5.0-8.2 oleic-, and 1.0-2.6
linoleic-acids (C.S.I.R., 1948-1976).
Following oil extraction from
copra, the coconut cake (poonac) contains 10.0-13.3% moisture,
6.0-26.7% oil, 14.3-19.8% protein, 32.8-45.3% carbohydrates, 8.9-12.2%
fibers, and 4.0-5.7% ash.
The so-called coconut water is 95.5%
water, 0.1% protein, <0.1% fat, 0.4% ash, 4.0% carbohydrate. Per
g water, there is 105 mg Na, 312 K, 29 Ca, 30 Mg, 0.1 Fe, 0.04 Cu, 37
P, 24 S, and 183 mg choline. Leaves contain 8.45% moisture, 4.282 ash,
0.56% K2O, 0.25 P2O5, 0.28 CaO, and 0.57% MgO.
to 27 m or more tall, bearing crown of large pinnate leaves; trunk
stout, 30-45 cm in diameter, straight or slightly curved, rising from a
swollen base surrounded by mass of roots; rarely branched, marked with
rings of leaf scars; leaves 2-6 m long, pinnatisect, leaflets 0.6-1 m
long, narrow, tapering; inflorescence in axil of each leaf as spathe
enclosing a spadix 1.3-2 m long, stout, straw or orange colored, simply
branched; female flowers numerous, small, sweet-scented, horne towards
top of panicle; fruit ovoid, 3-angled, 15-30 cm long, containing single
seed; exocarp a thick fibrous, husk, enclosing a hard, bony endocarp or
shell. Adhering inside wall of endocarp is testa with thick albuminous
endosperm, the coconut meat; embryo below one of the three pores at end
of fruit, cavity of endosperm filled in unripe fruit with watery fluid,
the coconut water, and only partially filled when ripe. Fl. and fr.
year round in tropics.
from the Indochina-Indonesia and Hindustani centers of origin, coconut
has been reported to tolerate high pH, heat, insects, laterites, low
pH, poor soil, salt, sand, and slope. Many classifications have been
proposed for coconuts, none is wholly satisfactory. Variations are
based on height, tall (27 m or so) or dwarf (2 m); color of plant or
fruit; size of nut (some palms have very large fruits, others have
large numbers of small fruits); shape of nuts, varying from globular to
spindel-shaped or with definite triangular sections; thickness of husk
or shell; type of inflorescence; and time required to reach maturity.
botanical varieties and forms have been recognized and named, using
some of the characteristics mentioned above. Cultivars have been
developed from various areas. Dwarf palms occurring in India are
introductions from Malaysia, live about 30-35 years, thrive in rich
soils and wet regions, flower and fruit much earlier than tall
varieties, and come into bearing by fourth year after planting.
However, dwarf varieties are not grown commercially, and only on a
limited scale because of their earliness and tender nuts, which yield a
fair quantity of coconut water. They are highly susceptible to diseases
and are adversely affected by even short periods of drought.
coconuts are commonly grown for commercial purposes, 40-90 years, are
hardy, and thrive under a variety of soil, climatic, and cultural
conditions, begin to flower when about 8-10 years after planting. 2n =
pantropical, especially along tropical shorelines, where floating
coconuts may volunteer, the coconut's origin is shrowded in mysteries,
vigorously debated. According to Purseglove (1968-1972), the center of
origin of cocoid palms most closely related to coconut is in
northwestern South America. At the time of the discovery of the New
World, coconuts (as we know them today) were confined to limited areas
on the Pacific coast of Central America, and absent from the Atlantic
shores of the Americas and Africa. Coconuts drifted as far north as
Norway are still capable of germination. The wide distribution of
coconut has no doubt been aided by man and marine currents as well.
from Subtropical Dry to Wet through Tropical Very Dry to Wet Forest
Life Zones, coconut has been reported from stations with an annual
precipitation of 7-42 dm (mean of 35 cases = 20.5), annual temperature
of 21-30°C (mean of 35 cases = 25.7°C) with 4-12 consecutive
frost free months, each with at least 60 mm rainfall, and pH of 4.3-8.0
(mean of 27 cases = 6.0).
by seedlings raised from fully mature fruits. Seeds selected from
high-yielding stock with desirable traits. Yield of copra is final
criterion, based on size and number of nuts per palm.
should have straight trunk and even growth, with closely spaced
leaf-scars, short fronds, well oriented on the crown, short bunch
stalks, and from palms growing under normal rather favorable
conditions. Also the inflorescence should bear about 100 female
flowers, and the crown should have a large number of fronds and
consequently of inflorescences.
Seednuts should be medium-sized and
nearly spherical in shape; long nuts usually have too much husk in
relation to kernel. Because male parent is unknown and because female
parent is itself heterozygous, seednuts from high-yielding palms do not
necessarily reproduce same performance in progeny; so that character
alone has limited value. Records are kept of fruits harvested from each
mother palm, such as number of bunches, number of nuts, weight of
husked nuts, estimated weight of copra (about one-third weight of
husked nuts being considered favorable). After fully mature nuts are
picked, and not allowed to fall, they are tested by shaking to listen
for water within. Under-ripe, spoiled, those with no water, or with
insect or disease damage are discarded.
Nuts are planted right away
in nursery or stored in a cool, dry, well-ventilated shed until they
can be planted. Seeds planted in nursery facilitate selection of best
to put in field, as only half will produce a high-yielding palm for
copra. Also, watering and insect control is much easier to manage in
nursery. Soil should be sandy or light loamy, free from waterlogging,
but close to source of water, and away from heavy shade. Nursery beds
should be raised about 22 cm, and long, separated by shallow drains to
carry away excessive water. In preparation of nursery beds, they should
be dug and loosened to a depth of 30 cm. Loosened soil mixed with dried
or rotten leaves and ash from burnt fresh coconut husks at a rate of 25
lbs. of husk-ash per 225 sq. ft. Nuts spaced in beds 22 x 30 cm, a
hectare of nursery accomodating 100,000 seednuts. Nuts planted
horizontally produce better seedlings than those planted vertically.
The germinating eye is placed uppermost in a shallow furrow, about 15
cm deep, and soil mounded up around, but not completely covering them,
leaving the eye exposed. Soaking nuts in water for 1-2 weeks before
planting may benefit germination; longer periods of soaking are
progressively disadvantageous. Bright sunlight is best for growing
stout sturdy seedlings. Regular watering in nursery is essential in dry
weather, amount and frequency depending on local conditions. Mulching
sometimes used to preserve moisture and supress weeds. Paddy straw,
woven coconut leaves, and just coconut leaves are used; howevers they
might encourage termites. Potash fertilizer helps seedling growth, and
probably do not need other fertilizers as nut provides most of needed
About 16 weeks after nut is planted, the shoot appears
through the husk, and at about 30 weeks, when 3 seed-leaves have
developed, seedlings should be planted out in permanent sites. Rigorous
culling of seedlings is essential. All late germinators and very slow
growers are discarded. Robust plants, showing normal rapid growth,
straight stems, broad comparatively short dark-green leaves with
prominent veins, spreading outward and not straight upward, and those
free of disease symptoms, are selected for planting out. Best spacing
depends upon soil and terrain. Usually 9-10 m on the square is used,
planting 70-150 trees/ha; with triangular spacing of 10 m, 115
palms/ha; and for group or bouquet planting, 3-6 palms planted 4-5 m
apart. Planting holes of 1 m wide and deep should be dug 1-3 months
before seedlings are transplanted. In India and Sri Lanka, 300-400
husks are burned in each hole, providing 4-5 kg ash per hole. This is
mixed with topsoil. Two layers of coconut husks are put into bottom of
hole before filling with the topsoil mixed ash. Muriate of potash, 1 kg
per hole, is better than ash, but increases cost of planting. The earth
settles so that it will be 15-30 cm below ground level when seedling is
planted. In planting, soil should be well-packed around nut, but should
not cover collar of seedling, nor get into leaf axils. As plant
develops, trunk may be earthed up, until soil is flush with general
ground level. Usually 7-8 month old seedlings are used for transplants.
In some instances plants up to 5 years old are used, as they are more
resistant to termite damage. If older plants are used, care must be
taken not to damage roots, as they are slow to recover. Desirable to
transplant in rainy season. In areas with only one rainy season per
year, it is simpler to plant nuts in nursery in one rainy season, and
transplant them a year later.
Young plantation should be fenced to
protect plants from damage from cattle, goats, or other wild animals.
Entire areas may be fenced in, individual trees, or, as in Sri Lanka
and southern India, piles of coconut husks are placed around tree. At
end of first year after transplanting, vacancies should be filled with
plants of same age held in reserve in nursery. Also any slow-growers,
or disease damaged plants should be replaced.
During first 3 years,
seedling should be watered during drought, an application of ca 16
liters/tree twice a week being recommended. Keep trees clear of weeds,
especially climbers. Usually a circle 1-2 m in radius should be weeded
with mattock several times a year, the weeds left as mulch.
Cover-crops, as Centrosema
or Pueraria phaseoloides,
are used and turned under before dry season. Catch-crops as Cassava (Manihot utilissima),
and green gram (Vigna
aureus) and cowpea (Vigna
bananas and pineapples, may be used. Sometimes bush crops, in addition
or instead of, ground covers are used as green manures, as Tephrosia candida, Crotalaria striata, C.
uraramoensis, C. anagyroides, all fast growers. Gliricidia sepium and Erythrina lithosperma
may be grown as hedges or live fences, their loppings used as green
the cheapest form of fertilizer materials for a given area are used.
General fertilizer recommended, used with suitable local modifications,
would consist of 230-300 g N, 260-460 g P2O5, and 300-670 g K2O per
palm. Application of lime is not generally recommended.
There is no
evidence that salt is beneficial as is sometimes claimed. They can
withstand a degree of salinity, about 0.6%, which is lethal to many
other crops. Palms seem to need some magnesium, but are extremely
sensitive to an excess. Cultivation depends on soil type, slope of
land, and rainfall distribution; often disk-harrowing at end of monsoon
rains to control weeds is all that is necessary (Reed, 1976).
begin to yield fruit in 5-6 years on good soils, more likely 7-9 years,
and reach full bearing in 12-13 years. Fruit set to maturity is 8-10
months; 12 months from setting of female flowers.
Nuts must be
harvested fully ripe for making copra or desiccated coconut. For coir
they are picked about one month short of maturity, so that husks will
be green. Coconuts are usually Picked by human climbers, or cut by
knives attached to end of long bamboo poles, this being the cheapest
method. With pole, a man can pick from 250 palms in a day, by climbing,
only 25. In some areas nuts are allowed to fall naturally, and
Nuts are husked in field, a good husker
handling 2,000 nuts/day. Then nut is split, (up to 10,000 nuts per
working day). Copra may be cured by sun-drying, or by kiln-drying, or
by a combination of both. Sun-drying requires 6-8 consecutive days of
good bright sunshine to dry meat without its spoiling. Drying reduces
moisture content from 50% to below 7%. Copra is stored in
well-ventilated, dry area.
Extraction of oil from copra is one of the oldest seed-crushing
industries of the world.
cake is usually retained to feed domestic livestock. When it contains
much oil, it is not fed to milk cows, but is used as fertilizer.
coconut is just the white meat, the brown part is peeled off. It is
usually grated, but may be thread or chip. Dried in driers similar to
those for tea. Good desiccated coconut should be white in color, crisp,
with a fresh nutty flavor, and should contain less than 20% moisture
and 68-72% oil, the extracted oil containing less than 0.1% of free
fatty acid, as lauric.
Parings, about 12-15% of kernels, are dried
and pressed for oil yielding about 55%. Used locally for soap-making.
The resulting poonac used for feeding draught cattle.
is made from desiccated coconut with oil removed, and the residue dried
and ground. However, it does not keep well.
Coir fiber obtained from
slightly green coconut husks by retting in slightly saline water that
is changed frequently (requires up to 10 months); then, husks are
rinsed with water and fiber separated by beating with wooden mallets.
After drying, the fiber is cleaned and graded. Greater part of coir
produced in India is spun into yarn, a cottage industry, and then used
for rugs and ropes. In Sri Lanka, most coir consists of mechanically
separated mattress and bristle fiber. To produce this, husks are soaked
or retted for 1-4 weeks, and then crushed between iron rollers before
fibers are separated. Bristle fibers are 20-30 cm long; anything
shorter is sold as superior mattress fiber. In some areas, dry milling
of husks, without retting, is carried on and produces only mattress
The separated pith, called bast or dust, is used as
fertilizer since the potash is not leached out. Coconuts may be stored
at temperature of 0-1.5°C with relative humidity of 75% or less for
1-2 months. In storage, they are subject to loss in weight, drying up
of nut milk and mold. They may be held for 2 weeks at room temperature
without serious loss.
Yields and Economics
copra, an average of 6,000 nuts are required for 1 ton; 1,000 nuts
yield 500 lbs. of copra, which yields 250 lbs. of oil. Average yield of
copra per ha is 3-4 tons. Under good climatic conditions, a fully
productive palm produces 12-16 bunches of coconuts per year, each bunch
with 8-10 nuts, or 60-100 nuts/tree. Bunches ripen in about 1 year, and
should yield 25 kg or more copra.
For coir, 1,000 husks yield anout
80 per year, giving about 25 kg of bristle fiber and 55 kg of mattress
fiber. Efficient pressing will yield from 100 kg of copra,
approximately 62.5 kg of coconut oil, and 35 kg coconut cake, which
contains 7-10% oil. The factor 63% is generally used for converting
copra to oil equivalent. Yields of copra as high as 5 MT/ha have been
reported, but oil yields of 900-1,350 kg/ha. Pryde and Doty (1981) put
the average oil yield at 1,050 kg/ha, Telek and Martin (1981), at 600
kg/ha. World production of coconut oil is more than 2 million
tons/year, about half of which moves in international trade.
coconut produced in countries where palm are grown and the products
exported. Sri Lanka, Philippine Islands, Papua, and New Guinea are the
largest producers. United States and United Kingdom each import at
least 50 million pounds annually. Only about 40% of copra produced is
exported, remaining 60% processed into oil in country of origin. United
States annually imports 190 million pounds of coconut oil and more than
650 million pounds of copra; some sources state 300,000 tons copra and
over 200,000 tons coconut oil annually. Coconut oil ranks third, after
soybean and peanut oil, in world production of oils. I predict palm oil
(Elaeis) will soon move up.
coconut of commerce weighs 0.5-1.0 kg. According to Purseglove, the
average number of nuts per hectare varies from 2,500 to 7,500
indicating yield of ca 1,200 to 7,500 kg/ha. On the one hand, 'Jamaica
Talls' fruits average 1.7 kg, nuts 0.7 kg, of which 50% is endosper; on
the other, 'Malayan Dwarfs' fruits average 1.1 kg, the nut 0.6 kg,
yielding 0.2 kg copra (6,000 nuts/ton copra).
yields of copra (3-8 nuts per kg copra) range from 200 kg/ha in
Polynesia to 1,200 kg/ha in the Philippines, suggesting coconut yields
of 1,000 to 8,000 kg/ha. Since about 60% of this constitutes the
inedible fruit husk and seed husks, I estimate the chaff factor at 0.6.
oil, cracked at high temperatures will yield nearly 50% motor fuel and
diesel fuel. Coconut destructive distillation is reported to yield
11.5% charcoal, 11% fuel gas, 37.5% copra spirit, 12.5% olein
distillate, 1% crude acetate, 0.15% glycerol, and 0.85% acetone plus
methanol. As of June 15, 1981, coconut oil was $0.275/lb., compared to
$0.38 for peanut oil, $1.39 for poppyseed oil, $0.65 for tung oil,
$0.33 for linseed oil, $0.265 for cottonseed oil, $0.232 for corn oil,
and $0.21 for soybean oil (Chemical Marketing Reporter, June 15, 1981).
At $2.00 per gallon, gasoline is roughly $0.25/lb. Quick (1981) tested
linseed oil (Iodine number 180) which cokes up fuel injectors in less
than 20 hours and rapeseed oil (Iodine number ca 100) which logs into
the hundreds of hours before the onset of severe injector coking.
Coconut oil (Iodine number 10) should be a very good candidate from
this viewpoint. This could be very important in developing tropical
countries where diesel fuel is scarce and often more expensive than
coconut oil. One Australian patent suggests that distillation of
coconuts at 550° gave 11.5% charcoal, 11% fuel gas, and 37.5% copra
spirit, 12.5% olein distillate, 12.5% black oil, 1% crude acetic acid,
0.15% glycerol, and 0.85% (acetone + methanol) which natural
fermentation takes to 2.7-5.8% ethanol. Of course, you can't have your
coconut toddy and eat or drink or burn it too (Duke, 1977b).
Coconuts are subject to numerous fungal diseases, bacterial infections,
and the most serious virus-like disease, cadang-cadang.
trees are also attacked by numerous nematodes and some insect pests,
the most damaging insect being the black beetle or rhinoceros beetle (Oryctes rhinoceros),
which damages buds, thus reducing nut yield, and breeds in decaying
and pests of a particular area should be considered and local agent
consulted as to how to deal with them. Agriculture Handbook No. 165
(1960) lists the following as affecting this species: Aphelenchoides cocophilus
(red ring disease), Cephalosporium
Diplodia epicocos, Endocalyx melanoxthanus, Endoconidiophora paradoxa
(leaf-bitten disease, leaf scorch, stem-bleeding), Gloeosporium sp., Pellicularia koleroga (thread
palmarum (gray leaf spot, leaf-break), Phomopsis cocoes
(on nuts), Phyllosticta
sp. (on leaves), Physalospora
fusca (on leaves), P.
rhodina (on roots and trunk), Phytopthora palmivora
(bud rot, leaf drop, wilt), Pythium
Analysis of Biomass Fuels
62 kinds of biomass for heating value, Jenkins and Ebeling (1985)
reported a spread of 20.05 to 19.02 MJ/kg, compared to 13.76 for
weathered rice straw to 23.28 MJ/kg for prune pits. On a % DM basis,
the fiber dust contained 66.58 % volatiles, 3.72 % ash, 29.70 % fixed
carbon, 50.29 % C, 5.05 % H, 39.63 % O, 0.45 % N, 0.16 % S, 0.28 % Cl,
and undertimed residue.
Agriculture Handbook 165. 1960. Index of plant diseases in the United
States. USGPO. Washington.
Duke, J.A. 1972. Isthmian ethnobotanical dictionary. Publ. by the
author. Harrod & Co., Baltimore.
Duke, J.A. and Wain, K.K. 1981. Medicinal plants of the world. Computer
index with more than 85,000 entries. 3 vols.
Hartwell, J.L. 1967-1971. Plants used against cancer. A survey. Lloydia
Jenkins, B.M. and Ebeling, J.M. 1985. Thermochemical properties of
biomass fuels. Calif. Agric. 39(5/6):14-16.
E.H. and Doty, H.O., Jr. 1981. World fats and oils situation. p. 3-14.
In: Pryde, E.H., Princen, L.H., and Mukherjee, K.D. (eds.), New sources
of fats and oils. AOCS Monograph 9. American Oil Chemists' Society.
Purseglove, J.W. 1968-1972. Tropical crops. 4 vols. Longman Group Ltd.,
Purseglove, J.W. 1972. Tropical crops. Monocotyledons 2. John Wiley
& Sons, New York.
G.R. 1981. A summary of some current research in Australia on vegetable
oils as candidate fuels for diesel engines. (Abstr.) Seminar II, USDA,
Reed, C.F. 1976. Information summaries on 1000 economic plants.
Typescripts submitted to the USDA.
L. and Martin, F.W. 1981. Okra seed: a potential source for oil and
protein in the humid lowland tropics. p. 37-53. In: Pryde, E.H.,
Princen, L.H., and Mukherjee, K.D. (eds.), New sources of fats and
oils. AOCS Monograph 9. American Oil Chemists' Society. Champaign, IL.
Last update July 8, 1996