Is Jatropha Worth the Trouble?
Dr. Saturnina Halos, chairman of the Department of Agriculture's Biotechnology Advisory Team, said in a forum on biofuels that jatropha contains neurotoxins capable of killing humans and animals. So far, there are two known cases of poisoning. In 2007, 21 grade school students in the island village of Tubigon, Bohol were rushed to hospital after they ate the fruit of the tuba-tuba, jatropha's local name. Another case of poisoning happened in Cansilayan, Murcia, Negros Occidental, where 10 children ate jatropha seeds.
Many marginal lands, usual suggested areas for jatropha growing in developing countries, are communal grazing areas. Jatropha can harm livestock. In one experiment (Adam, 1979) jatropha curcas was fed one time to six calves at doses of 2.5, 1 and 0.25 g/kg and given to two other calves at 0.025 g/kg for 14 days. All calves in the first group died within 19 hours. The two calves that received low doses daily showed signs of poisoning and died by the 14th day after they were fed jatropha .
An irritant, jatropha causes abdominal pain and nausea half an hour after ingestion. Depression may occur, especially in children. Two seeds serve as a strong purgative. Four or five seeds are enough to kill. Jatropha seeds contain toxalbumin curci, a deadly substance.
Jatropha is not suitable for purposes other than biofuel production. As more developing countries rush to secure a place in the biofuels market, a glut is not too far in the offing. When this happens, farmers will be hard put to find alternative markets for their seeds and oils. Today, there are now 21 countries that produce biodiesel.
Jatropha also takes a long time to grow. Farmers will have to two years before they can harvest seeds. Optimum fruiting happens five years after planting.
Competitor for land
Promoters of jatropha growing claim jatropha can be grown on marginal, even acidic, lands. University of the Philippines – Los Banos professors Ted Mendoza and Oscar Zamora, in their paper “Jatropha: What the Public Should Know, point out the error that jatropha can thrive even in poor soil. They write: "Jatropha grows well under a favorable growing environment -high soil fertility, adequate moisture and weed management during its early yerars of growth".
Also, studies in India have shown that, without irrigation, the average yield after five years is only 1.1–2.75 tonnes per hectare, compared with 5.25–12.5 tonnes per hectare when irrigated. Another study (Giles Clark, May 2008) said that though the plant can adapt to poor-quality soils, better oil yields can only be obtained when fertilizers are used.
It seems likely that, instead of being grown in mainly in marginal areas, jatropha for agrofuels will compete directly with food crops for the most fertile, irrigated lands.
Planters in other countries have experienced frustrations in growing jatropha.
In the early 1990s, a growth trial in Nicaragua covering 2,000 hectares did not live up to expectation, yielding only a disappointing 200 litres of oil per hectare. The program was stopped after it proved to be not profitable to small farmers.
A USAID-sponsored study in Malawi found jatropha planting an unsuitable project for improving the livelihood of smallholders. According to Africa's Kruger Park Times, the study came to the conclusion that the strength of the market for Jatropha products” was “unfounded”.