Last updated: 3rd October 2002

Family: Euphorbiaceae

Genus: Ricinus

Species: communis

Source: http://www.poison.org/prevent/documents/plantImages/castor1.jpg

Contents

General Background
Details of Quality Characteristics
Current Production and Yields
Constraints upon Production
Markets and Market Potential
Other Information
Research
Useful Websites
BioMat Net
Contacts
References

General Background
An annual or perennial oilseed originating in East Africa, especially Tanzania, Kenya, Uganda, it can be found on waste land there in all but the driest places. The plant has a substantial tap root with many lateral branches which can reach a great depth. Annual cultivated varieties reach a height of 0.9 - 1.5m whilst natural perennial varieties can grow as tall as 6m. As a species, the plants are very variable. Leaves are large, glossy and green with pointed lobes and prominent veins, each develops on a long stalk.

The inflorescence consists of an erect panicle with female flowers at the top and male flowers at the bottom. The female flowers open before the male flowers and hence there is a large degree of cross-pollination. The flowering period may be long. The fruits are spherical capsules which become hard and brittle. The seed capsule has thick walls, is spiny and contains 3 coci. Each cocus contains one seed.

Short Term (annual) varieties tested in East Africa:

Advantages of annual varieties: Higher yield potential, seeds seldom shatter and have uniform hull strength and thickness.

Disadvantages of annual varieties: Pest susceptibility

Perennial castor self seeds or is semi-cultivated in East Africa. Occasionally it is sown as a pure stand at a spacing of 2 x 2 m. Sometimes ratooned to prevent being blown over. The seed is collected from ground and dried capsules are picked from the plants.

Castor has been grown experimentally in France and has also been grown in Romania and the Ukraine.


Details of Quality Characteristics
The castor bean contains 50-55% oil. The oil itself contains a number of fatty acids similar to those in cooking oils, such as oleic acid, linoleic acid, stearic acid and palmitic acid. However, among vegetable oils, castor oil is distinguished by its high content (over 85%) of ricinoleic acid. No other vegetable oil contains so high a proportion of fatty hydroxyacids. Castor oils unsaturated bond, high molecular weight (298), low melting point (5ºC) and very low solidification point (-12ºC to -18ºC) make it industrially useful, most of all for the highest and most stable viscosity of any vegetable oil (Bonjean, 1991).

Properties of Caster oil:

Oil Composition:

Current Production and Yields

A large part of world production and development of castor oil is by members of the "International Castor Oil Association" (ICOA).

Leading producers of castor oil : China, India and Brazil. Together they account for 90% of the acreage and production of castor beans. It is grown in former USSR, Costa Rica, Ecuador, Pakistan, Thailand, Philippines, Paraguay, Romania, Ethiopia, Sudan, Tanzania, Mexico. World-wide production stood at 1, 227, 669 tonnes in 2000 (FAO).

Grown in test plots in France, during the late 1980`s, newer varieties have produced between 2.0 and 2.7 t/hectare of seed over a three year period. Under cropping conditions, the output in France is between 1.5 and 2.0 t/ha of seed, mainly because the chemical removal of weeds had not been perfected. These seeds would contain 50-55% oil. (Bonjean, 1991)


Constraints upon Production
The regions in which castor may be grown as a commercial crop are restricted by lack of frost tolerant types and the need for high temperatures (optimum 20 - 25ºC, over 4.5 - 6 months) and low atmospheric humidity to achieve good yields. Only Southern Europe is potentially suitable for castor production.

For annual varieties the seedbed must be weed free as young plants are delicate. Good weed control is essential, both pre- and post-emergence. In the early stages of the crop mechanical cultivation is inadvisable. Sow to avoid wet weather in 2nd half of the crops life. A maize planter can be used for sowing, with suitable plates and a spacing of approximately 0.9 x 0.3m.

Pests - in Africa there are a great variety of pests, up to 50 species of insect can damage castor, including grasshoppers, various larvae, and the more serious pests: capsid bugs, green stink bugs, lygus bugs, Helopeltis. Sucking pests cause damage by puncturing, rather than actual sucking. Whether these would also be a problem in Europe is unknown.

Diseases seldom do much damage - leaf spot (Cercospora reicinella), Rust (Melampsora oricini) and Alternaria Leaf spot may occur.


Markets and Market Potential
Caster oil is sold either for pharmaceutical or industrial use. Specification for pharmaceutical use can be found in the European Pharmocoepia. The industrial type may be divided into ‘first’, ‘second’ and ‘third’ quality. Only pressed castor oil, extracted without solvents, can be called ‘first quality’. These oils, produced in Europe, are virtually colourless and have very low acidity. ‘Second’ and ‘third’ quality oil are commercial names, meaning that the oil has been extracted using solvent.

35-55% of the seed content is a valuable drying oil with many industrial applications.

The primary use of Castor oil is as a basic ingredient in the production of nylon 11, sebacic acid, plasticisers and jet engine lubricants, nylon 6-10, heavy duty automotive greases, coatings and inks, surfactants, polyurethanes, soaps, polishes, flypapers, paints, varnishes, lubricants, and many other chemical derivatives and medicinal, pharmaceutical and cosmetic derivatives.

The plant is also used for fibre, an insecticide and repellent. Cellulose from the stems is used for making cardboard and paper products.

The oil from the seed is a very well known laxative and purgative that has been widely used for over 2,000 years. It is so effective that it is regularly used to clear the digestive tract in cases of poisoning. The oil has a remarkable antidandruff effect. The oil is well tolerated by the skin and so is sometimes used as a vehicle for medicinal and cosmetic preparations. Castor oil congeals to a gel-mass when the alcoholic solution is distilled in the presence of sodium salts of higher fatty acids. This gel is useful in the treatment of dermatosis and is a good protective in cases of occupational eczemas and dermatitis. Medicinal applications consume a tiny fraction of total production.

The seeds and residual cake are highly poisonous and unless processed to remove the poisons cannot be fed to livestock. In some countries the cake is used as a fertiliser. Poisons contained in the cake include ricin.


Other Information
Seeds are sown with a spacing of 90cm between rows and 50cm within rows. Seed is sown 5cm deep. Castor prefers deep sandy loam soil with a pH of 6, but it can be cultivated on a wide variety of soils with pH range of 5 - 8. Both annual and perennial plants set seed poorly if there is wet weather during flowering. It is also highly intolerant of water-logging and requires free draining soils. Due to the penetrating root system the perennial plant is drought resistant. Castor does not tolerate salt. Unbalanced nitrogen application encourages growth of foliage at the expense of flower and seed formation. Good yield responses have been obtained from 75kg/ha of nitrogen and 25kg/ha of both Phosphate and Potash.

Weed control is essential; some pre-emergence herbicides may be suitable but subsequent measures are also likely to be required. It is uncertain whether pests and diseases of the crop in tropical areas will also become problems in Europe. The most troublesome fungus for castor in Europe is thought to be Alternaria ricini.

The seed pods of perennial varieties shatter easily so have a lower yield potential than annual varieties, thus exhibit great differences in hull thickness and strength even on the same inflorescence, making mechanical hulling difficult. Their cultivation needs little attention.


Research
Researchers are currently trying to establish a suitable agronomic practice for castor production in Southern Europe. Breeding goals include improvement in seed yield, oil content and ricinoleic acid content. The breeding of genetically modified oilseed rape, producing ricinoleic acid, is under active development, but it seems unlikely that this would replace castor where this can be grown economically.


Useful Websites

http://www.comp.leeds.ac.uk/pfaf/D_search.html - Plants for a future: A resource centre for edible and other useful plants


BioMat Net

Castor oil (Ricinus communis)

AIR3-CT94-2324 - Coordinated Improvement of Castor Oil Productivity and Quality for New Potential European Markets

AIR1-CT92-0069 - GEIE EURORICIN: Covering European Needs of Castor Oil, Using Community Grain

AGRE-0039 - Seed Oils for New Technical Applications SONCA

AIR2-CT93-1817 - Vegetable Oils with Specific Fatty Acids (VOSFA) Agricultural and Industrial Development of Novel Oilseed Crops


Contacts


References

• Journal of American Oil Chemists Society (1988). Vol. 65 (12).

• Bonjean, A., (1991), Le Ricin. Galileo, France.