Natural rubber cultivations can yet be made profitable | Sunday Observer

Natural rubber cultivations can yet be made profitable

The national rubber yield in Sri Lanka is hovering around 800 to 1,000 kilograms per hectare per annum over the past five decades. However, this is despite of the fact that the Rubber Research Institute of Sri Lanka introducing to growers good agricultural practices that allow them to achieve an average cycle yield of around 2,000 kilograms per hectare per annum.


Currently recommended rubber clones to the growers have twice as much yield potential relative to what was available to the growers about five decades ago. Young budded planting material now recommended and made available to the industry has the capacity to give a complete stand of vigorously growing plants in our rubber cultivations and is much superior to bear root budded stumps used by the rubber growers earlier.

Undoubtedly, the present day pesticides show much more efficiency in pest and disease control whilst being environmentally friendlier. Tapping is yet continuous excision as done previously, but low frequency tapping systems with the use of stimulants are introduced with the objective of addressing industry issues such as worker shortages, shortening of tapping cycle, lower harvester productivity and high tapping costs.

To overcome the loss of crop due to interference of rain on harvesting, the time tested technology of rain guards have been introduced to the growers. Chemical fertilizer to revenue rubber is based on foliar analysis through which growers could provide the precise type and quantity of nutrients to the plantations at a much lower cost.

Mentioned above are a few key good agricultural practices the rubber growers could adopt for improved land productivity, profitability and overall performance.

The scientists of the Rubber Research Institute of Sri Lanka are of the opinion that with the correct adoption of technological advancements listed above, during the peak yielding phase of the tapping cycle a land productivity level of around 3,000 kilograms per hectare per annum could be achieved against a peak yield of around only 1,500 kilograms per hectare per annum that was possible earlier.

However, the ground reality is that we are yet to see a significant increase in the national yield levels over the past five decades despite of the fact that the potential yield has almost doubled during that period. Economic losses to the growers and eventually to the country due to this huge gap between the potential and actual land productivity levels will be colossal.

Therefore, one has to find out the exact reasons for this low and stagnating national yield levels enabling to develop strategies to address them.

Possible factors preventing productivity improvement

Simultaneously to the development of novel technologies targeting productivity enhancements in the rubber plantations, the available natural resources and also the business environment in the plantation industry have also changed. The negative impacts due to changes in natural resources and business environment could prevent achieving productivity improvements through technological advancements if appropriate changes are not made to mitigate them.

Though rubber plantations commence with a total stand per hectare of around 520, at the end of the economic life cycle it falls to about 350–375. Further, the productive stand contributing to the yield is even less than this and it is around 250. The reason for the difference between total and productive stand is the incidence of Tapping Panel Dryness, a physiological disorder resulting in non-yielding trees upon tapping though the trees look healthy. Wind and animal damages and also the incidence of white root disease are the major reasons for the decline in the total stand.

A complete healthy stand is a must to achieve potential land productivity. The scenario of the gradual decline in the productive mature stand to about half of what it ideally should be has serious implications on land productivity and profitability. However, it should be emphasised that the phenomenon of Tapping Panel Dryness is yet not well understood even by the scientists and it is on the increase with the introduction of relatively high yielding clones even under good management practices.

Hence, the management of the plantations do not have complete control over the resulting loss of land productivity caused by Tapping Panel Dryness.

A rubber tree cannot be tapped to harvest latex if the tapping panel of the tree is wet as it leads to infections in the tapping panel causing the bark of the tree to rot and hence lowering of the trees yield potential.

Some are of the opinion that tapping of wet panels could also lead to Tapping Panel Dryness.

As a result of interference of rain on harvesting, in the traditional rubber growing areas of Sri Lanka we lose around 30% of the potential crop each year. This crop loss is through no tapping, late tapping and washout days.

It has become apparent that the recent changes in climatic conditions, i.e. extreme and unpredictable weather conditions, have further increased crop losses due to interference of rain on harvesting.

The fertiliser recommendation based on foliar analysis provides only the essential nutrients to the plants. With this approach the cost of fertilizer is minimized. If this most essential and minimal nutrient need is not given to the plantations attributing to reasons such as cash flow issues negative impacts on productivity would be inevitable. The capacity of the soil to retain both nutrients and moisture is also a key factor that governs tree health and its yield. The present rubber cultivations are about the third or the fourth generation. Hence the health of soil in present rubber plantations is much poorer than what it was five decades ago. In the circumstances investment on key agricultural practices such as fertiliser application and soil and moisture conservation are vital and has become a fundamental need.

Currently, plantations experience a severe shortage of workers. This leads to the inability of adopting recommended agricultural practices on time and also adopting them meeting the desired quality standards.

Impact of worker shortage on harvesting is currently very severe. Studies conducted by the Rubber Research Institute of Sri Lanka reveals that the loss of crop due to lack of harvesters and also by employing unskilled harvesters to meet the requirement is more than 20%. Similarly, implementation of important agricultural practices connected to replanting is also hampered by worker shortages leading to sub-standard rubber clearings with relatively low yield potentials.

The writer is a former Chair, Department of Plantation Management, Wayamba University of Sri Lanka and Director, Rubber Research Institute of Sri Lanka.