Archives

by Dr. L.M.K. Tillekeratne, Director, Rubber Research Institute of Sri Lanka

Guayule, commonly pronounced as Vayoolee is a plant originating in Maxican deserts, containing natural rubber latex in its stem and in branches. This alternate natural rubber (NR) source is also known as Spanish rubber as it was discovered by Spanish adventurists as far back as 1550.

Since then there have been attempts by North American and South American countries to plant this on a commercial scale for the extraction of NR. There are reports appearing in international news bulletins and in local newspapers about a possible threat to the natural rubber industry from this alternate source of natural rubber. This article analyses the conditions under which American authorities have taken steps to grow this rubber source on the American and Mexican border during the past and the pros and cons of this plant and the rubber obtained from it in comparison with the rubber from the Hevea brasiliencis tree, commonly known as the Asian rubber tree.

Guayule plant, botanically known as Parthenium argentatum, is in the same family as Pathenium histerosperm which was causing a major health hazard for the people in the North and the East of Sri Lanka when it was accidentally introduced to the country through the Goats imported by the Indian Army (IPKF).

This Pathenium histerosperm, commonly known as Parthenium weed was causing allergies and even shocks to people farming in these areas in a very big way. Hence, the Department of Agriculture had to take strict measures to destroy it at sight to completely eliminate if from the soil of Sri Lanka. Hence, if the histerosperm species of the parthenium family is causing so much danger to human beings, there is every possibility for the argentatum species of the same family and genus of Parthenium to cause various health problems to human beings.

Natural rubber extracted from the common Hevea tree is believed to be causing on allergy to some small percentage of people mainly due to the presence of leachable low molecular protein in the rubber extracted from the tree. If that is the case with NR of Hevea origin, the rubber extracted from the parthenium family member Guayule must be several times more health risky and harmful to human health.

The Guayule plant growing up to a height of 3ft. under desert condition needs only a rainfall of 200-400 mm per annum compared to 2750 to 5000 mm rain needed by the hevea tree. Guayule can withstand a day time desert temperature going up to 50 C. The plant is harvested after 3 years by cutting from the bottom of the tree, leaving the root stock for ratoons to grow. This 2nd generation of plants is also harvested in another 3 years along with the roots thereby making the land available for replanting.

Branches and stem of the Guayule plant free of leaves are then crushed in a machine and extracted with a solvent for rubber. It has also been reported that the new extraction techniques utilise water as the solvent and the light guayule latex floating on the surface can then be collected and converted to dry Guayule rubber.

The main problem associated with this new form of desert rubber is its very high cost of extraction by means of solvents. In 1910, the cost of production of a kilo of Guayule rubber had been above 1 US dollar. The other major problem associated with this desert rubber is that it contains a very high resin content compared to normal NR, thereby making it unsuitable for making some dynamic rubber appliances. According to reports, in 1910, 10,000 MT of Guayule rubber had been produced in Mexico. But the Mexican revolution at 1910 had destroyed the plantation and the extraction plants during this period.

In 1920, as the demand for NR increased, US authorities had taken measures to grow Guayule again in Mexico and Southern USA. However, with the drastic drop of NR price in the world market, in 1929 this project had been abolished.

World war 2 increased the demand for NR in the world market. Further, as most of the SE Asian NR producing countries were closely aligned to Japan, US government started planting Guayule in 30 countries in Europe and in America including Spain. Even Australia joined USA in this affair to produce rubber needs for the allied armies. But when the war was over, mainly owing to the high cost of production of Guyayle rubber, the plantation was abandoned again.

The next attempt to increase Guayule rubber production had been planned by the USA in 1972 when OPEC countries started increasing price of oil randomly. In 1978 America had allocated over $30 million for research in Guayule cultivation and manufacture.

At present, the productivity of Guayule in Mexico is only about 475 Kg/ha/yrs compared to not less than 2000 kg/ha/yrs given by Hevea rubber. But, with modern research, it is not impossible to increase the productivity of Guayule rubber to the level of Heave rubber. Similarly the possibility is also there with modern research to lower the cost of manufacture of Guayule also by a fair percentage. If that is the case, it will be possible to bring the cost of production of Guayule rubber closer to the COP of Hevea rubber.

Then there is a definite danger for the Hevea rubber growers in the SE Asian countries from the cheap Guayule rubber of American origin.

Further, from the points mentioned above it is clear that both US and European countries had increased Guayule production during the past only when the NR price in the world market was very high and was unaffordable to the rubber products manufacturers to use it for their industries. From this, the clear massage given by the Americans and Europeans to the NR producers in the world is that if NR price is increased randomly; they have an alternate source of rubber to be grown in their deserts.

Hence, the NR producing countries should not try to push the price of NR too high in the world market over and above a certain limit. Instead, to make higher profits from their plantations, they must increase productivity of their rubber lands to realistic levels as maintained in India of 2500 kg/ha/yr.

If attempts are made to increase the rubber prices too high with the view to making high profits, that will be an invitation for the American continent to plant Guayule in their deserts.

The above productivity level of 2500 kg/ha/yr can only be achieved if all farmers and small holders follow RRI recommended correct agronomic practices in their farmlands. Even attempts made to overexploit the plantation by stimulation or by another means might produce even worse results. Nearly 29000 ha of lands abandoned in elevations above 1000 ft and bellow 25000 ft should also be utilised for rubber plantation to produce rubber for the growing needs of the country.

Growing rubber in these areas will not only provide latex to the end products industries; but would also provide firewood and some timber requirements of the nation while creating a better forest cover for the country from which we can earn more money under the carbon sequestration mechanism in the near future.

www.crescat.com

News | Business | Features | Editorial | Security
Politics | World | Letters | Sports | Obituaries

Produced by Lake House
Copyright © 2003 The Associated Newspapers of Ceylon Ltd.
Comments and suggestions to :Web Manager