Jatropha curcas cultivation.

Germplasm

Reported from the Central and <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />South American Centers of Diversity, physic nut, or cvs thereof, is reported to tolerate Slope. There is an endemic species in Madagascars J. mahafalensis, with equal energetic promise. (2n = 22)

Distribution

Though native to America, the species is almost pantropical now, widely planted as a medicinal plant which soon tends to establish itself. It is listed, e.g., as a weed in Brazil, Fiji, Honduras, India, Jamaica, Panama, Puerto Rico, and Salvador (Holm et al, 1979).

Ecology

Ranging from Tropical Very Dry to Moist through Subtropical Thorn to Wet Forest Life Zones, physic nut is reported to tolerate annual precipitation of 4.8 to 23.8 dm (mean of 60 cases = 14.3) and annual temperature of 18.0 to 28.5°C (mean of 45 cases = 25.2).

Cultivation

Grows readily, from cuttings or seeds. Cuttings strike root so easily that the plant can be used as an energy-producing living fence post.

Harvesting

For medicinal purposes, the seeds are harvested as needed. For energy purposes, seeds might be harvested all at once, the active medicinal compounds might be extracted from the seed, before or after the oil, leaving the oil cake for biomass or manure.

Yields and Economics

According to Gaydou et al (1982), seed yields approach 6–8 MT/ha with ca 37% oil. They calculate that such yields could produce the equivalent of 2,100–2,800 liters fuel oil/ha (see table under Energy). In Madagascar, they have ca 10,000 ha of purging nut, each producing ca 24 hl oil/ha for a potential production of 240,000 hl (Gaydou, et al, 1982).

Energy

The clear oil expressed from the seed has been used for illumination and lubricating, and more recently has been suggested for energetic purposes, one ton of nuts yielding 70 kg refined petroleum, 40 kg "gasoil leger" (light fuel oil), 40 kg regular fuel oil, 34 kg dry tar/pitch/rosin, 270 kg coke-like char, and 200 kg ammoniacal water, natural gas, creosote, etc. In a startling study, Gaydou et al. (1982) compare several possible energy species with potential to grow in Malagasy. Oil palm was considered energetically most promising.

Biotic Factors

Agriculture Handbook No. 165 lists the following as affecting Jatropha curcas: Clitocybe tabescens (root rot), Colletotrichum gloeosporioides (leaf spot), and Phakopsora jatrophicola (rust).