Rubber growers yet to reap benefits from excellent trading
conditions
Dr. Asoka Nugawela, Director, Rubber Research
Institute of Sri Lanka
Natural rubber in the raw form is currently trading at around Rs. 250
per kilogram. Very often the prices improve further when the supply
cannot meet the demand for this raw material. But whether the rubber
growers are reaping the full benefit of this healthy trading condition
is a question.
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A rubber plantation in Kegalle |
Since the national productivity level is presently in the region of
1150 kilograms per hectare per year which is significantly lower than
the potential it is obvious that the majority of the rubber growers are
not taking the maximum benefit from this golden opportunity.
This article attempts to identify the possible reasons for this
rather unhealthy situation for the growers in order to assist them in
developing strategies to overcome this situation.
If well managed during both immature and mature periods a rubber
grower could obtain a yield of around 1000 kilograms of rubber per year
from an acre. With the current farm gate price this amount of rubber has
a value of Rs. 250,000.
But the majority of our rubber growers are able to get only about 500
kilograms of rubber from an acre during a year for which the value is
just half of the potential, i.e. Rs. 125,000.
Even with such sub optimal land productivity levels the rubber
growers are making reasonable profits and there is lot of enthusiasm in
further investing in rubber cultivations.
However, it should be emphasised at this point that the profits
generated by the growers’ to-day are driven by the natural rubber prices
and not by the effort of the management to enhance productivity.
If we could achieve the latter as well we could enhance profitability
and thereby reap the maximum benefits of good trading conditions whilst
sustaining profitability even under adverse trading conditions.
A concerted effort to enhance land productivity whilst benefiting the
grower in the first instance will be a tremendous boost to the
development of the rubber industry of the country as well.
The rubber products manufacturing sector of the country is developing
very fast. One limiting factor for continuous growth is the inadequate
supply of the raw natural rubber to the end user.
Enhanced productivity levels whilst addressing this issue will boost
the economy of the country through increased foreign exchange earnings
and employment generation.
The land productivity levels of the rubber growers are sub-optimal
due to many reasons. Some of these issues could be rectified in the
short run whilst the rest will need long term attention for
rectification.
Through short term methods only, the growers cannot achieve the
potential yields. For example one major reasons for sub-optimal land
productivity is the poor tappable stand per hectare. Though the yield
and income loss due to this factor is significant it is not possible to
rectify this situation in mature rubber cultivation.
This is a fact that the growers should bear in mind in order to be
rectified during future replanting and new planting.
In the short term the harvested crop could be increased by about 20%
if fields that were not fertilised are fertilised correctly. The mature
rubber needs only one application of fertiliser per year.
The fertiliser quantity per tree and the mixture to be used varies
with the age of the tree and the region in which the cultivation is
found. Information on these aspects is given in the table.
To achieve the optimum benefits from fertilising, high quality
fertiliser has to be used in correct quantities, at the correct time of
the year using correct methods. For mature rubber, fertiliser needs to
be applied once the new foliage is mature and with the onset of rains.
Generally these conditions occur in the month of April each year. The
ability of the rubber tree to absorb fertiliser is highest at this time
of the year. The fertiliser has to be applied in about 4 points at least
3-4 feet away from the base of the tree and at a depth of ca. 6” from
the soil surface.
The feeder roots are well distributed in this area to absorb the
fertiliser and burying of fertiliser will prevent any losses of
fertiliser due to washing off or volatilisation.
The holes necessary to apply the fertiliser has to be dug using
forks. If mamoties are used that will result in damaging of all the
feeder roots in the area the fertiliser is applied preventing the
fertiliser being absorbed into the plant (Fig. 1).
Another way of increasing yields in the short term is to adopt
correct tapping methods which will enable to harvest potential yields of
individual trees in a holding. The tapping methods and systems adopted
should enable the grower to obtain highest possible yields at the lowest
cost for a period of at least 24 years from each tree.
Some basic things we should remember are to tap the tree from high
left to low right at a 30 degree angle to the horizontal axis.
The length of the tapping cut should be a half spiral, i.e. one half
of the tree. During tapping the thickness of the shavings should not be
more than 1/20th of an inch.
Removing a thicker shaving will not result in high yields but will
only reduce the number of years a rubber tree could be tapped. It is
apparent that rubber trees are tapped only for 16-18 years though they
could be tapped for a period of 24 years.
For the grower to ensure that the factors discussed above regarding
tapping are correctly adopted in their holdings and also to help the
latex harvesting officers to practise correct tapping the rubber trees
should be marked with guidelines each year.
The guidelines will help the latex harvesting officers to control the
tapping angle, thickness of a shaving and the length of tapping cut
during tapping. Further these guidelines will help the land owner to
monitor whether the latex harvesting officers have tapped the rubber
trees correctly.
The guidelines should be drawn on the rubber trees each year using a
stencil. They need to be drawn correctly and the latex harvesting
officers should be made aware of the uses of it.
If otherwise it will only add to the costs of the grower with no gain
to the land owner. One other important factor during tapping is to
control the depth of the tapping cut. It should not be too deep to
damage the cambium tissue of the bark.
Cambium tissue is responsible for renewal of the bark and hence if it
is removed there will be no bark renewal after the tapping of virgin
panels. Therefore, tapping of renewed bark will not be possible leading
to a significant reduction in the number of years a rubber tree could be
tapped.
If the cambium is only partially damaged that will also lead to
uneven bark renewal making tapping difficult and yields uneconomical.
Correct tapping
To facilitate quality tapping the landowners need to provide the
latex harvesting officers with quality tapping knives. Further they need
to be sharpened as and when needed.
Commencing tapping early in the day when the light permits to do so
is another strategy to increase yields. Prior to the sunlight falling on
to the rubber trees the turgour pressure within the latex vessels of the
rubber trees is very high.
When the latex vessels are cut during tapping at this time of the day
the latex flow rate is high resulting in a high latex yield. Further
tapping of a task should not be commenced from the same tree each day
the tapping block is tapped.
The tree tapped last today should be tapped first on the next tapping
day. By this way the land owner could ensure that the quality of tapping
and quantity of latex harvested will be uniform among all trees in each
tapping block.
Interference of rain on tapping is a major constraint for the rubber
growers to harvest latex, if the tapping panels of the rubber trees are
wet due to rain tapping is not recommended as it will result in panel
diseases.
Further if the tapping panel is wet the latex will flow out of the
tapping cut resulting in wastage of latex. In the wet zone of the
country where the majority of the rubber plantations are found out of
the 365 days in a year generally only 200 normal tappings are possible.
Out of the balance 165 days about 50 late tappings could be
undertaken. However, rubber smallholders undertake late tapping only
very rarely.
On a late tapping day there is a decline in the crop and this could
be up to 25% of the normal tapping crop.
Accordingly the rubber growers loose more than 115 tapping days, i.e.
1/3rd of the potential tapping days in a year resulting in a similar
loss of the potential annual crop.
The resulting income loss to the latex harvesting officers, land
owners and country will be of the same magnitude. This huge loss could
be overcome by the use of rainguards systematically.
This is a technology the Rubber Research Institute has been
recommending for the past 20 years or so. Nevertheless the adoption rate
of this technology is rather low despite of its ability to enhance the
income levels of the latex harvesting officers, land owners and the
country significantly.
Correct use of rainguards
The factors highlighted above, i.e. correct use of fertiliser,
systematic tapping and use of rainguards have the ability to double the
productivity levels of our rubber cultivations in the short term.
Corresponding to this doubling in productivity there will be a similar
enhancement in the income levels of the rubber growers and latex
harvesting officers.
A collective effort by all the rubber growers will be a tremendous
boost to the economy of the country.
When investing on future rubber re-plantings or new plantings the
investors have to ensure that agronomic practices possible of giving
yields of 1000 kilograms per acre per year are adopted.
These agronomic practices will be the strategies to be adopted in
order to the rubber growers and to the country obtain the maximum
benefit from the high rubber prices.
The economic benefits the growers obtain from high productivity
levels and prices should be passed on to the workers.
This whilst enhancing the worker productivity will help to sustain
their services to the industry.
In our new clearings the preliminary work has to be done as per the
recommendations.
The correct removal of the old rubber stand, adoption of soil and
moisture conservation practices, lining and holing to achieve
recommended planting distances and stand per hectare are some important
agronomic practices in this context governing productivity.
A rubber plant once established will have to be kept for 30 years.
Hence we just can not compromise on the quality of the plants for any
other need of the grower. ‘The growers need to ensure that they plant
only the good quality plant and the plants are not disturbed during
either transportation or planting.
If disturbances do occur at these stages it will definitely have a
negative impact on the early growth of the plant and could be considered
as a waste of a quality rubber plant.
Quality plants have to be used
It is apparent that the animal damage is a serious threat to the new
rubber clearings and such damages are on the increase. The main culprit
is reported to be the wild boar. The situation gets aggravated due to
the poor fencing of the clearings. Such animal damage to new clearings
has to be completely eradicated.
A strong barbed wire fence could successfully eliminate this threat.
The quality of the fence can not be compromised for costs or any other
factors if the grower is very serious in controlling the problem.
The base of the rubber plants up to a radius of at least 3 feet has
to be kept weed free to prevent competition for fertilizer and moisture.
With regard to the fertiliser use, the mixtures, quantities, application
methods and timing have to be correct.
These aspects are vital for the quality of the clearing. Cover crops
are helpful in further improving the quality of rubber clearings. They
contribute to enhancing soil moisture and fertility levels whilst
reducing the weeding costs.
If young rubber plants do not show any signs of branching even after
reaching a height of 8-9 feet branching have to be induced. Recommended
methods have to be adopted for this purpose.
Branching at this stage whilst minimising wind damage will result in
higher growth rates due to increased food production by the plant
through increased foliage and light capture.
Both root and foliar diseases can cause plant death resulting in
lowering of the plant stand. This happens only when the diseased plants
are not identified early and treated. Hence such diseases have to be
identified as early as possible and treated using recommended methods.
If the new rubber clearings are managed as discussed above all plants
in a clearing should show a growth rate of at least 10cm or above per
annum at a height of 120cms from the bud union whilst maintaining the
stand per hectare.
If there are plants showing lesser growth rates they need to be
identified and treated with the objective of boosting their growth
rates. Use of compost and split application of fertiliser are some
methods that could be adopted to treat the under performing plants to
improve their growth.
The land owners should have the required level of commitment to
achieve these standards in their holdings. The reward for such
commitment will be a rubber clearing tappable after five years of
establishment and with a yield potential of over 1000 kilograms of dry
rubber per acre per year.
This will enable the grower to reap the maximum benefits from the
prevailing and anticipated higher prices in the future.
Further the land owner will be able to survive in an unlikely event
of the rubber prices crashing and will be in a position to obtain the
services of the workers by offering them competitive wages. Such land
owners will be contributing to the economy of the country in an active
manner.
Fertiliser recommendation for mature smallholdings
Region Age of Holding
Urea ERP MOP
Kegalle and Virgin bark 200 100 100
Kurunegala
Renewed 150 75
bark
Others Virgin bark 200 100 200
Renewed 150 150
bark |
