Jatropha Anyone?

Rafaela T. Calendacion, Ph.D.
University Extension Specialist
University of the Philippines, Los Baños

As the era of cheap oil comes to an end, the search for alternative sources of energy becomes a race against time. There are a number of crops that may be tapped for renewable sources of bio-energy and Jatropha curcas is one of them. It could be the start of economic upliftment for the people in areas where it can be grown as an agro-industrial venture. Planting Jatropha will require mill construction in the areas where the oil will be processed. Transport of the harvested fruits from the farm to the mill will require that roads and bridges be constructed and an efficient transport system be provided.

With all these prospects, will planting Jatropha provide the financial benefits it promises, particularly to the farmers who will be growing it?

With this question a study was conducted and published in the Philippine Journal of Crop Science Vol. 32 No 1 titled "Towards Making Jatropha curcas (Tubang bakod) a Viable Source of Biodiesel in the Philippines ".

In this study, it was found that Jatropha becomes a viable source of biodiesel at a pump price of PhP40.00 (US$0.80) per liter of dinodiesel, assuming high fruit yields of 36,000 kg /ha, high rates of oil extraction (34% and 38%) and with by-products included as added farm income in addition to sales of oil.

At low yield levels (12,000 kg/ha), it will become profitable for farmers growing it if the current Philippine dinodiesel pump price increases to about PhP90.00 (US$1.80) per liter at a 30% rate of oil extraction (These estimates exclude processing and marketing costs). The inherently low Jatropha seed yield explains the low revenue.

Research must be done to further increase the seed yield of the Jatropha plant and to find ways to maximize total farm yield with the inclusion of by-products. The relatively long gestation period of 5 years before the crop reaches optimum fruiting and the low seed yield of Jatropha requires that optimal crop mixes (multiple cropping schemes) or compatible diverse cropping involving short maturing crops and high value fruit/wood trees to increase the total farm yield as a risk-minimizing farm strategy. Diverse cropping and multiple cropping models must be emphasized by both the public and private entities promoting the massive planting of Jatropha.

Recognizing that the technology for Jatropha processing is yet to be established in the country, to develop these options 3 to 4 years after planting is too short a time. It is necessary to accelerate research efforts on the optimization of processing raw oil into trans-esterified oil and the processing of by-products (press cake and/or glycerol) into high-priced products.

Jatropha oil has a high saponification value, making it an excellent substrate for soap-making. Two products may then be profitable from Jatropha: soap and biodiesel.

There are equally important issues that should be clarified with respect to the planting of Jatropha:

1) It can grow in marginal soil but growth and yield will be slow and marginal or low. This recalls the saying that you can not get something from nothing.

2) It can survive dry weather but it will shed leaves to avoid dying due to excessive loss of water. When it sheds leaves due to excessive water loss there is no growth and no fruit set. It resumes growth once the soil is moist again.

3) Parties interested in growing Jatropha should understand that Jatropha grows well and delivers a high yield under favorable growing conditions - high soil fertility, adequate moisture, and weed management - during its early years of growth.

4) Jatropha is a sun loving crop. While it grows under shade, photosynthesis (growth and yield) will be affected proportionally by the degree of shading.

5) The current big push to grow Jatropha, especially with the use of imported seeds, should be done with great care. Importing the high yielding varieties may also mean importing unknown bad traits of the plant with regards to pest susceptibility. It would be extremely frustrating to find out 5 years after planting them that the imported high-yielding variety is susceptible to local viral or fungal diseases. Moreover, it may even provide an inoculum source, thus infecting even the indigenized cultivars in the country.