OPINION:Way forward towards self-sufficiency in natural rubber 

Prof. Asoka Nugawela

By Emeritus Professor Asoka Nugawela, Wayamba University of Sri Lanka and former Director, Rubber Research Institute of Sri Lanka

Natural rubber is a commodity in which the potential for value addition is at a very much higher level than any of the other commodities. Adding value and exporting against exporting of raw rubber enhances foreign exchange earnings to the country whilst generating more employment opportunities. The rubber product manufacturing sector in Sri Lanka has shown a remarkable growth in the recent years. Presently the rubber product manufacturing sector of the country requires around 135,000 metric tons of natural rubber per annum. However, the country is not able to produce this quantity of natural rubber compelling to import around 66,000 metric tons of natural rubber to the country annually. Sri Lanka spends around Rs. 16 billion to import natural rubber to bridge the supply and demand gap of country. This trend whilst creating a pressure on countries limited foreign exchange reserves is also a hindrance for the development of the natural rubber industry in the country. Thus, there is an urgent need for relevant stakeholders of the industry to endeavour towards making Sri Lanka self-sufficient in its natural rubber requirement.
Natural rubber production in the country
The total extent and productivity together determine the rubber production of any country. In Sri Lanka the area under rubber cultivation has shown a declining trend from 133,100 ha in the year 2014 to 126,700 ha in the year 2018. Though the land productivity stood at 914 kg/ha/year in the year 2014 it too had gradually declined to 853 in the year 2018). The declining trends in both factors that determine the total production, i.e. land extent and productivity, from year 2014 to 2018 have led to the declining trend in our total production as well during the same period. In order to arrest this declining trend in total natural rubber production in the country, as a short-term strategy increasing productivity of existing rubber lands and as a long-term strategy increasing the land area through establishing rubber cultivations having high yield potential need to be implemented. 
Table 1. Natural rubber production, exports, imports and local consumption in metric tons.
Year    Production    Exports    Imports    Local consumption
2014    98,600    16,300    26,326    108,626
2015    88,600    10,400    54,376    132,576
2016    79,100    16,100    72,985    135,985
2017    83,100    17,200    61,801    127,701
2018    82,560    14,000    66,640    135,200

Table 2. Rubber land area and productivity 
Year    Land area (Ha)    Land productivity (kg/ha/year)
    Total    Mature    Replanting    New planting    
2014    133,100    107,800    2,897    1,561    914
2015    132,800    107,600    1,917    825    823
2016    132,700    98,900    1,467    615    800
2017    130,300    98,600    1,338    677    842
2018     126,700     96,800    1,507      1,209    853 

Why is land productivity low?
As per the planting density recommended by the Rubber Research Institute of Sri Lanka, around 520 rubber plants should be planted in a land extent of one hectare. If all 520 plants planted in a hectare of land are vigorously growing and healthy, each plant will have the potential to yield around 5 kilograms of dry rubber per annum at maturity except during the initial 2 to 3 years of tapping. To harvest this potential 5 kilograms of dry rubber from a plant the quality of harvesting/tapping has to be good and also harvesting should be undertaken uninterruptedly during each year. With a possible 340-350 days of harvesting per annum, the number of tappings on a single tree would be either around 172 or 115 for once in two (d/2) and three (d/3) day tapping systems respectively. If these factors governing yield is achieved it is apparent that the potential from rubber cultivations is around 2,600 kilograms of dry rubber per hectare per annum during peak yielding periods which is around 300% more than the current national land productivity level of 853 kilograms of dry rubber per hectare per annum.
However, it must be stated that 100% of the potential yield stated above cannot be practically achieved under commercial conditions. Uncontrollable factors like heterogeneity in soil conditions and adverse climatic conditions contribute to deviations. Further, controllable factors like lapses in management, availability and skill levels of workers including harvesters and levels of adopting good agricultural practices also leads to deviations from potential performance. The level of actual performance in rubber cultivations we witness today partly reflects the deviations from good agricultural practices recommended to the growers. 
Though the rubber growers’ plant 520 plants in a hectare of land, the average number of plants remaining at the time of commencement of tapping which is generally 6 to 7 years after planting is found to be around 460. Use of poor-quality plants, incorrect technique of planting, adverse weather for planting, lightning damages, leaf & root diseases and animal damages largely contribute to this reduction in stand per hectare. The loss of stand per hectare continues even after commencement of harvesting. Surveys conducted have revealed that the loss of stand per hectare could be as much as 0.75% per annum during the 24-year tapping cycle of a rubber cultivation. This would mean that at the end of the economic lifespan of a rubber cultivation, on average the remaining stand will be around only 380 plants per hectare. Another significant factor that lowers land productivity is the physiological disorder Tapping Panel Dryness (TPD). Trees affected with tapping panel dryness though look healthy would not yield any latex upon tapping using recommended tapping systems. At the commencement of tapping all the 460 plants (the average number of plants present in a hectare at the time of tapping) will yield. However, each year the number of trees that would get affected with TPD will increase and towards the end of the 24-year tapping cycle it could be as high as around 25%. Thus, at the end of the tapping cycle the number of yielding rubber trees present in a hectare of land would be only around 285, i.e. 25% less from 380. Accordingly, the average number of yielding trees during the 24-year tapping cycle will be 373 {(460+285)/2}. If the potential 5 kilograms of rubber per tree per annum could be achieved from this number of trees the average land productivity during the 24 - year tapping cycle would be 1,865 (373 * 5) kilograms per hectare per annum. This is a 30% reduction of the potential land productivity of 2,600 kgs per hectare per annum. Thus, what is apparent is that lowering of productive rubber stand per hectare due to various reasons identified above alone reduces the land productivity by about 30% from the potential.
Commencement of tapping at the correct vegetative growth stage of the plant and use of chemical fertilizer as recommended by the Rubber Research Institute are also factors essential to build tree vigour and obtain 5 kilograms of dry rubber per tree per annum. However, commencement of tapping prior to reaching the correct growth stage and deviations in the use of chemical fertilizer can often be observed in rubber cultivations. On average this reduces the yield potential per tree per annum from 5 to around 4 kilograms further lowering the land productivity from 1,865 to 1,492 (4 x 373) kilograms per hectare per annum. 
Due to deviations from the expected level of management and adoption of agricultural practices the yield potential of a rubber tree could drop to 4 kilograms from 5 kilograms per tree per annum as discussed. Another condition that we need to fulfill even to obtain 4 kilograms of rubber per tree annum is to undertake the required number of tappings per tree per annum. Relatively high rainfall and high number of wet days in the traditional rubber growing areas in the country is a hindrance to achieve the required number of tappings per tree per annum to obtain the potential yield. Rain leads to no tapping days, late tapping days and also washouts all leading to crop losses. Studies have revealed that around 30% of the potential crop is lost due to interference of rain on harvesting. 
The availability of adequate number of skilled harvesters is another factor needed to obtain the potential yield of a tree. However, rubber growers very often complain of lack of adequate number of skilled harvesters. Studies conducted in this regard revealed that around 20% of the potential crop is lost due to lack of adequate number of skilled harvesters in the rubber industry. Therefore, the total impact of rain and lack of adequate skilled harvesters on rubber tapping leads to about a 50% (30% + 20%) loss of potential crop in rubber cultivations. Accordingly, the land productivity level will further fall from 1,492 to 746 (50% of 1,492) kilograms per hectare per annum. According to the industry statistics the national yield level is 853 kilograms per hectare per annum and this could be possible as there are some rubber cultivations with good management and high level of technology adoption which can push the overall national productivity to a higher level. It should be stated that countries like India, Thailand, Vietnam and Malaysia have demonstrated the possibility of achieving national yield levels of around 1,500 kilograms per hectare per annum and also sustaining it.
Economy of rubber growers   
As stated previously the national productivity of rubber lands in Sri Lanka is 853 kilograms per hectare per annum.  The current trading conditions in the country enable the rubber growers to sell their produce at the rate of around Rs. 250 per kilogram of dry rubber. Accordingly, the gross income from a hectare of rubber land per annum will be Rs. 213,250 (Rs. 250 x 853). Though the land productivity levels and natural rubber prices are at a relatively low level in the country, the worker wages, cost of adopting agricultural practices like weeding, fertilizing, disease management and also the cost of other inputs are increasing each year. In this background a gross income of Rs. 213,250 per annum from a hectare of rubber land is inadequate to cover the costs whilst rubber growers obtaining a reasonable income for the investment they have made.  Due to such poor cashflows the rubber growers’ lose interest in managing their rubber lands systematically. This scenario leads to the deterioration of the rubber cultivations further leading to a vicious cycle. It needs to be emphasized that rubber growers should endeavour to improve cashflows through achieving high land and worker productivity levels rather than depending on the price to which the country does not have total control. 
Though the majority of the rubber growers in the country are of the situation described above, there are those who manage their plantations satisfactorily achieving land productivity levels of the region of 1,500 kgs hectare per annum. Such growers are able to get a gross income level of around Rs. 375,000 (1,500 x 250) per annum even under the current trading conditions. This income level is comparable with that of well managed tea and coconut cultivations. Further, with regard to rubber and coconut at the end of the economic life span of the crop a good income could be obtained by selling of the remaining trees. This income could be in the region of Rs.800,000 for both crops. Thus, if growers’ endeavour to adopt good agricultural practices they are still able to achieve a reasonably high return on investment even under current trading conditions and costs. At the same time, it should be stated that there are other plantation crops with the potential of achieving much higher return on investments. Cinnamon and palm oil for example are some of them and are able to give a gross income of over Rs. 1,000,000 per hectare per annum. Thus, for the betterment of the national and plantation economy and for high income levels of the growers and workers such crops too should be planted in relatively large extents in the country.
It is apparent that with good agricultural and management practices, investments on rubber cultivation too can yield a reasonable return on investment. Relevant authorities need to give that confidence to the growers and also have in place systems to provide them with necessary technology, advisory services, assistance in marketing, inputs such as quality planting material and fertilizer together with strict monitoring systems in place. Institutions responsible to provide these services need strengthening to build the capacity to fulfil their mandate.
Increasing national rubber production:
Short-term strategies
There are number of interventions to be done to the existing mature/revenue rubber cultivations to enhance production in the short-term run. Due to limited inputs and low level of adoption of essential agricultural practices partly driven by poor income levels, tree vigour and health in most of the existing mature/revenue rubber cultivations are rather poor. This situation could be corrected to a certain degree by adopting good agricultural practices such as fertilizer application, soil and moisture conservation and disease management uninterruptedly. Factors like poor quality of tapping and not undertaking tapping in all possible tapping days too could be rectified in the short-term to enhance national rubber production. Though most growers complain about lack of skill harvesters resulting in poor quality tapping and also inability to tap due to interference of rain, technology available to mitigate such adverse impacts are hardly adopted. Popularizing low frequency tapping to-gether with yield stimulation is the way forward to address crop losses caused by a shortage of skilled harvesters.  Interference of rain on rubber tapping leads to significant crop losses and the correct adoption of rain guarding technology would address this issue. The interventions stated above, to deal with poor tree health, shortage of skilled harvesters and interference of rain on tapping have a potential to enhance the national rubber production by around 50% in the short run.
Long-term strategies
The relatively low number of rubber trees per hectare and the poor vigour of the existing trees due to non-adoption of recommended tapping policies together with poor systems and quality of harvesting cannot be rectified in the existing cultivation itself. However, these factors contribute significantly to lower the national rubber production. With this background and knowledge, rubber growers need to pay emphasis on achieving the recommended stand per hectare in all future newly planted and replanted rubber cultivations. Further, growers should endeavour to make each and every tree in their rubber cultivations vigorous plants. Correct land selection, land preparation, soil and moisture conservation, lining and holing, using quality plants, adopting correct planting technique, planting with the onset of monsoons, in filling vacancies and replacing weak plants up to the second year from planting, timely weeding, correct fertilizer application and timely interventions to control pest and diseases, are vital to achieve the recommended number of vigorously growing plants per unit land area. 

With necessary focus on factors identified above it is possible for growers to bring a newly planted rubber clearing into tapping in six years and also to have at least 480 vigorously growing plants per hectare at the time of commencement of tapping. In such rubber clearings through adoption of good harvesting practices/systems, use of skilled harvesters and rain guards a cycle average land productivity level of more than 1,600 kgs per hectare per annum could be easily achieved. The cycle average is lower than peak yields of around 2,500 kgs per hectare per annum due to loss of total and healthy stand due to diseases, wind, lightning and tapping panel dryness during the tapping cycle. 

Increasing the total land area under rubber is another long-term approach to increase national rubber production. Recent studies undertaken by the Rubber Research Institute of Sri Lanka had revealed that rubber cultivation in the country could be extended to the intermediate zone of the country. One challenge the rubber grower has to face when planting rubber in the intermediate zone is the impact of lesser annual rainfall and the lesser number of rainy days per annum on the field establishment and growth of plants especially in the initial two years. This situation together with the uncertainty of weather pattern could lead to plant death and poor growth vigour. Though rubber could be established even under these conditions’ investments on watering/irrigation during the first two years of a rubber clearing would help to achieve a high stand per hectare consisting of vigorous plants leading to high yield potentials during the maturity period. The intermediate zone of the country has many positive features for rubber cultivation. Abundance of land, relatively flat terrain, fertile soil, less potential for incidence of diseases, a greater number of tapping days per annum are a few of them.
Administering the rubber industry
The Ministry of Plantation Industries is mandated to be responsible to the rubber industry of the country. The Rubber Research Institute, Rubber Development Department and the Thurusaviya Fund are the three institutions coming under the ministry to serve the rubber industry. The Rubber Research Institute of Sri Lanka is responsible for technology development and dissemination, Rubber Development Department for subsidy payments, monitoring of rubber smallholdings and providing advisory services to them whilst the Thurusaviya fund assists the rubber smallholders in their processing and marketing of their produce. Accordingly, the country has a good institutional structure in place to work for the betterment of the industry. Anyhow, adequate financial and trained human resources and systems to retain the experienced and trained employees are vital to obtain the mandated services from these institutions.  Advisory boards consisting of members representing different stakeholders of the industry would help to focus the institutional work programmes to cater to the current industry needs and also to develop work plans to meet future challenges. 
Way forward 
Each year the country imports around 66,000 mt of natural rubber to bridge the gap in the raw material requirement of the natural rubber value addition sector. For this the country spends around Rs. 16 billion worth of valuable foreign exchange each year. However, the country has the necessary institutional structure, human resources, climatic conditions, land and investors to implement and operate the short- and long-term strategies identified above in order to produce our national requirement of natural rubber. Becoming self-sufficient in our natural rubber requirement and making the raw material available to the local rubber product manufacturer at a competitive price and at correct time whilst being a strength to them would help to attract more investors benefitting the rubber industry and the country as a whole. To sustain the growth of the rubber industry in the country it is vital that we protect the producer, i.e., the rubber grower. For this what is most important is the ability for rubber product manufactures to buy the natural rubber produced by our growers at a price so that they can earn a fair return on their investment which could drive them to invest on good agricultural practices that would lead to high land productivity. The country imports numerous value-added natural rubber-based products. One such widely imported item is tyres. If the Government could provide a competitive advantage to the local manufactures for such an item through appropriate tax structures, local manufacturers would develop capacity to enhance farm gate prices of natural rubber. The tea factory owners in the country use a formula to determine price for green leaves based on the selling price of their products. Maybe a similar system could be adopted in the rubber sector of the country as well though it may not be as easy as it is for the tea sector. It is very vital that both rubber producers and rubber product manufactures are benefited through more transparent and fair trading systems to ensure the sustainability of the industry as a whole.