Palakkad is an important Rubber growing district of Kerala. Karimba a village in Palakkad is famous for Rubber Nursery Last year, when I was at Karimba village of Palakkad, I visited a Co-operative Rubber processing and marketing society there. I am giving a detailed note as known to me as to how rubber is produced and processed for marketing. Some photos are also included to understand the process better.
Joseph Priestley, in 1770 in England, observed that a piece of the material from the tree was extremely good for rubbing out pencil marks on paper, hence the name “rubber”.
Many plants species produce natural rubber. But most plants are not economically viable to collect its latex. Source of natural rubber is limited to one species, namely Hevea brasiliensis.
It is a native of the Amazon basin. Unfortunately it is not a suitable place for commercial cultivation. It is introduced from there to countries like Indonesia, and Malaysia in late 19th century. It can be termed as the most far reaching and successful of introductions in plant history.
Experiment to start commercial cultivation was made in Botanical Gardens, Calcutta in 1873. The first commercial Hevea (rubber) plantations in India were established at Thattekadu in Kerala in 1902. But wide cultivation of rubber started after 1940 in Kerala.
All earlier plantations were raised from unselected seeds. As a result productivity was low. Selection work on rubber with a view to improving the planting materials and the introduction of vegetative propagation by budding and grafting led to the establishment of numerous valuable clones. Improvements are being made by tissue culture also.
Use fullness of Rubber
Rubber tree takes about 5 to 7 years for commercial tapping of the latex. During these years other crops like pineapple, plantain, ginger etc. are cultivated along with the young plants. Though the rubber tree last for about hundred years, commercial tapping is possible only till about 30 years. After that the tree is traded for slaughter tapping and timber. Slaughter tapping is intensive tapping which will yield as much possible latex during about two years before the tree is cut for wood. The rubber wood will get spoiled quickly unless chemically treated. Treated and seasoned rubber wood is very fine for furniture and looks very beautiful and lasting. So this saves the trees in the forest that other wise would have been used for the purpose. Ecologically it is good. It also enables rain bearing cloud to form rain in Kerala. Eco-friendly Natural Rubber plantations can tap vast global funding. If India argues and wins at the conference of parties for inclusion of the eco-friendly rubber cultivation for aid under the Clean Development Mechanism of Kyoto Protocol, Natural rubber plantations can avail themselves of the benefit of vast global funding.
Another by-product of rubber plantation is Honey. Although rubber plantation was identified as a source of honey since 1920′s, organised commercial exploitation of honey from rubber plantations in India is a relatively recent development under the auspices of Khadi and Village Industries Commission (KVIC), The available estimates on the production of apiary honey provided by KVIC underline the importance of rubber plantations as a source of honey. The rubber tree is a prolific source of honey which is obtained from the extra floral nectaries at the tip of the petiole, where the leaflets join. Honey flow period is between the months of January and March when the tender leaves sprout. (Yes honey from leaves.)
Cultivation and processing
Cultivation and processing latex required much skill. Present day method is as follows: fresh ripe seeds are collected from under the selected trees. It is germinated in a bed of moist river sand, kept moist for about 6 days. The sprouted plants are removed delicately in a bucket of water and one by one planted very carefully in plastic bags filled with soil. After about a month, budding and grafting is done. For this you require dormant sprout taken from high yielding variety of plants specially grown for the purpose. This is grafted to the young plant.
It is then nurtured for about a year after which it is ready for planting in the field. Farmers buy the plants from Nursery and plant it in their field. For about 7 years they will plant other crops also along with the young plants. After 7 years, other crops are stopped and a sort of leguminous pants are grown all over the field. This plants store nitrogen from air in their roots and so good for rubber to get the required nitrogen without much cost. It also cover the entire field like a green carpet avoiding large scale moisture evaporation as well as keeping other unwanted plants to grow in the field.
There are many specialised Rubber nurseries in Karimba village. They take on lease hundreds of acres of Paddy fields for this purpose. For land owners it is high income with no work at all. For the Nursery industry it is essential and very profitable.
Field for plantation is best on slopes of hill. It requires tropical climate, good rain and sun light. The soil should not retain stagnant water. Paddy fields which are not suitable for rubber are made suitable by digging deep canal and put the soil removed to raise the level of land, thus making it suitable for Rubber.
The main crop from a rubber plantation is latex; a milky white dispersion of rubber in water. Two to three hours after tapping, the latex collected in the cup is transferred to a clean bucket. About 70-80 per cent of the crop from a rubber plantation is in the form of latex.
The latex which gets solidified in the tapping panel (tree lace) and the collection cups (cup lump) also form part of the crop and are collected by the tapper in a basket just prior to tapping. The latex spilt and/or overflowed to the ground (earth scrap) when gets dried up is also collected as scrap once in a month. These are collectively called field coagulum. Latex and field coagula are highly susceptible to bacterial action and therefore it is essential to process these into forms that will allow safe storage and marketing.
Latex is a white or slightly yellowish opaque liquid with a specific gravity, which varies between 0.974 and 0.986. It contains Rubber-30-40%, Proteins-2-2.5%, Resins-1-2.0%, Sugars-1-1.5%, Water-55-65%. Ash -0.7-0.9%
Fresh latex, as it comes out from the tree is slightly alkaline or neutral. It becomes acidic rapidly due to bacterial action. The formation of organic acids neutralizes the negative charge on rubber particles and the latex gradually gets coagulated on keeping. Therefore, fresh latex cannot be kept for long without preservative treatment
The taper earmark three plots of trees that he can tap consecutively in three days, and that he can collect the latex from each within about 3 hours. The trees are not tapped daily. Recent studies show that the trees tapped daily and once in three days yield the same quantity of rubber ultimately. So the labour cost is reduced.
The tapper goes to the field early morning or before sunrise with a head light on as latex yield is more before the sun get much above. He has a razor sharp, specially shaped knife to tap (cut the bark of the Rubber tree slanting around the tree). The tree trunk should not be touched (only the bark to be cut) otherwise the tree will be spoiled. The latex start flowing in to the cup placed below. After cutting the last tree he starts collecting the latex into a clean bucket.
By about 9 am or earlier he will take it to his home or a collecting centre for further processing. Small producers have to depend on others for this purpose. Now- a -days Rubber co-operative societies are being formed for collecting processing and marketing the rubber. I am giving how it is done by them. It is more technical and quality maintained at the highest level.
They have collection centres around. Empty drums are sent there along with cylinders containing Ammonia gas. When farmers bring their latex to the collection centre, a sample is taken in a small bottle to determine the Dry Rubber Content later. After that the latex is filtered measured and poured into the drum. Ammonia gas is entered into it through a tube in measured quantity in order to preserve the latex and prevent it from coagulating. Same action is continued with all farmers who brought the latex. Details are recorded in the book. When sufficient quantity is available it is brought to the Society office in a truck.
Then officials checked the records and necessary entries are made
Afterwards Dry Rubber Content is tested from samples brought by measuring the volume and then dries it in an oven and measure in a balance. The DRC is recorded against each farmer in the record.
Then latex is filtered through fine mesh stain less steel sieves three in numbers. DRC of the gross content is determined. Then dilute the latex to a required consistency considering the DRC. This is poured into aluminium dishes. Formic Acid diluted to the required consistency considering the volume and the ammonia content, is then mixed in each dish, stir and remove the foam and bubbles on top of each dish. Dishes are kept overnight for coagulation. Next day the Coagulated thick rubber is separated from the water and passes it through a series of Rollers. The first one remove most of the water, second and third is grooved and so a pattern of groves are created on the surface of the sheets on both sides so that it dry quickly ( having more surface.) Two tanks are side by side filled with water. The pressed sheets are washed in the two tanks and place on a clean table.
The sheets then are hung on wires to drip dry.
These are removed to a drying chamber after about two hours. The sheets are hung on bamboo reapers in the chamber. It is not good to dry in sun as the ultraviolet rays reduce the quality. The drying chamber is heated to a specific temperature. The heat is obtained by the bio gas obtained.
A few logs are also burned so that the sheets get a coating of organic mater released by the burning of log. It will help to prevent mould to form on sheets. Daily the sheets are over turned. In about three for days it will be dried.
The waste water coming from the dishes and washing tanks contain protein and organic substances. This is used for making Bio gas. This bio gas is used for making the required current for the unit as well as gas for heating the sheets, thus saving precious wood.
During World War 2 when Japan over ran Indonesia and Malaysia, US and Great Briton get panicked. They thought of starting rubber planting in Haiti and producing Synthetic Rubber. They started making synthetic rubber which was made from petroleum products. It was cheaper. But now it is very costly. For Aircraft Tyre, Truck Tyre and radial tyres only Natural rubber can be used. You cannot even mix synthetic rubber for the purpose.
Rubber sheets are graded according to International standard. The cooperative society in Palakkad is now producing the 2nd best variety (that is grade 1). The best variety is difficult to obtain at present.
In Kerala, other than the society or Plantations, make only the 5th best and ungraded lot at preset. 2nd best is a great achievement.
Grading is done visually. All blemishes like dirt, foreign body either contained in the latex or adhered to the sheets at any time is considered a blemish. So it is necessary to take utmost care to get a neat, clean sheet, in Golden colour and transparent (Semi transparent.) It is to be packed carefully before despatch. Rubber board at Kottayam help in marketing, research, and propagating and educating the farmers for better planting methods.
All along the Highways in Palakkad, you can see rubber plantations which not only enhance the beauty of Kerala but also improve the economy of Kerala.