Rubber Research in Sri Lanka

The past 100 years and the future:

(Continued from last week)

The yield potential of the initially introduced Wickham collection was reported to be around 300 kg/ha/year. Through genetic improvements with regard to yield and disease resistance and by identifying suitable agronomic practices the scientists have improved the yield potential up to 3000kg/ha/year. This is a necessity to sustain the rubber industry in an environment of increasing costs and fluctuating prices.

Rubber cultivation in the country had been restricted to the low elevation areas of the wet zone due to the susceptibility of the then clones to common leaf diseases. Anyhow a need to increase the total natural rubber production in the country was felt to cater to the increasing demand for this commodity. Nevertheless, the availability of land in the traditional rubber growing areas of the country was a limitation for expansion of rubber cultivation.

Therefore suitable agronomic practices and clones have been developed by the scientists to expand rubber cultivation into areas marginal with regard to elevation and rainfall creating opportunities to expand the rubber cultivation in the country.

With this innovation rubber is now being extensively planted in the intermediate zone and in areas where the elevation is more than 300m above sea level.

Quality of planting material for establishing clearings is of utmost importance to achieve the potential yield of the clone used through achieving an optimum stand of vigorous plants. With this objective the young budding technique has been perfected to raise vigorously growing two whorled quality plants with a production period of nine months.

These plants are recommended to be field planted with only the base of the poly bag removed to ensure uninterrupted growth of the plant by preventing any disturbance to the root system during transferring to the field.

Circle weeding around the rubber plants especially during the immature period is very much essential though it is costly and labour intensive. Also, the use of manual methods and weedicides are not environmentally friendly. Recently, by using waste rubber from the dipped products industry a rubber mat was developed that could effectively and efficiently control the weed growth at the base of the rubber plants.

Among the many agronomic practices fertilizer application is an important recommendation that could influence performance of both immature and mature rubber. Further, it is a relatively costly practice for the growers to adopt. Nevertheless, based on extensive research and development work the cost to adopt the fertilizer recommendation is greatly reduced. Recommending of an integrated approach using locally available fertilizers, cover crops, organic fertilizers and site specific applications have resulted in reduced costs with no set back in the performance.

During harvesting quality standards with regard to slope and depth of tapping cut and thickness of bark shavings have to be achieved. Nevertheless, due to shortage of skilled latex harvesters such standards are not achieved in the field very often. The Rubber Research Institute has developed a tapping knife where even a less skilled latex harvester could achieve the required quality standards of harvesting. The benefit of this invention to the growers and the country is enormous.

Indiscriminate use of yield stimulants can adversely affect productivity and profitability of rubber plantations. Yield stimulants were initially introduced to the country with such recommendations soon after the discovery of yield stimulants. Anyhow, the Rubber Research Institute of Sri Lanka through extensive field trials recommended the judicious use of yield stimulants to the industry. The use of yield stimulants in such a manner will help the growers to overcome the shortage of skilled latex harvesters, reduce cost of tapping, and enhance earnings of the latex harvesters and to prolong the economic life span of rubber trees.

Due to rain rubber growers in the traditional rubber growing areas loose more than 100 days of tapping per annum. With the development of effective bitumen based sealant by the scientists of the Rubber Research Institute the rainguarding technology has been introduced to the industry. With the correct adoption of this technology around 80 of the tapping days lost per annum due to rain could be recovered. This will significantly enhance the earnings of the growers and also the latex harvesters. The plant pathologists have been successful in developing and introducing technologies to keep the rubber plantations healthy despite of threats from the ever changing pests and diseases.

Integrated pest management systems using cultural, chemical and biological methods are advocated for cost effective control of all economically important pest & diseases evident in the country. Also, measures have been taken to prevent the entry of devastating rubber diseases found elsewhere in the world.

(To be continued)

by Dr. A. Nugawela Director,

Rubber Research

Institute