C5d-AGRICULTURAL CROPS - CASH CROPS - RUBBER

RUBBER

INTRODUCTION: Natural rubber is an elastic hydrocarbon polymer that naturally occurs as a milky colloidal suspension, or latex, in the sap of some plants. It can also be synthesized. The entropy model of rubber was developed in 1934 by Werner Kuhn.

TEMPERATURE: 21 to 35 degree C . Average 25 degree C
RAINFALL: 200 cm to 400 cm of well distributed rain
SOIL: Porous and well drained laterite soil or alluvial soil.

METHODS OF FARMING:-
•Rubber plants are obtained by seeds or bud grafting .
•Grafting method is more popular

The rubber trees are grown in neat rows in small acreages by the owners. These are known as smallholdings.

PROCESSING:-

Natural rubber prodn begins with the collection of latex, a milky white substance produced by the cells of several plants..

Rubber tapping is hard work. It can starts as early as 2 am. The coolness of the early morning air encourages the latex to flow thus improving the yield

•However, the tapping will continue until late morning

•A special tapping knife is used to shear off a thin layer. of rubber tree's bark. Care must be taking not to cut too deep as this would injure the tree.

Rubber tapping is hard work. It can starts as early as 2 am. The coolness of the early morning air encourages the latex to flow thus improving the yield .

•The latex flows into the cup attached to the tree. By noon or early afternoon, the latex will have stopped flowing.

•The rubber tapper will then go back to each tree and empty the latex collected in the cups into the tin.

The tins of latex will be carried back to a small makeshift rubber "factory" in the smallholding .

•Here the latex is poured into moulds. Then formic acid is added to coagulate the liquid latex.

•This transforms the liquid latex into a firm solid block of rubber

•The block of rubber is initially rolled using a wooden roller so that it is thin enough for it to be rolled by the mangle machine.

•This is a picture of the mangle machine. It is the only piece of machinery required to make the rubber sheets.

•The rubber sheet is manually rolled using the mangle several times to make it thinner by squeezing out the water. This make it easier for the sheet to dry.

•The finished rubber sheets are then bought home for drying.

•The dried rubber sheet is golden brown as opposed to white initially.









•Here, the dried rubber sheets are stacked up waiting to be sold to the middlemen .

In places like Kerala, where coconuts are in abundance, the shell of half a coconut is used as the collection container for the latex.
•The shells are attached to the tree via a short sharp stick and the latex drips down into it overnight.

•The mixture is then applied mechanically to a base or is shaped, and the coated object or shaped mixture is placed in molds and vulcanized .

•This usually produces latex up to a level of half to three quarters of the shell. The latex from multiple trees is then poured into flat pans, and this is mixed with formic acid, which serves as a coagulant resulting in rubber crump.
•After a few hours, the very wet sheets of rubber are wrung out by putting them through a press before they are sent onto factories where vulcanization and further processing is done to it.

AREAS/STATES

•Kerala, Tamil Nadu, Karnataka, Andaman and Nicobar islands

USES

We depend so much on rubber that it would be almost impossible to get along without rubber. Rubber is especially useful for several reasons. It holds air, keeps out moisture and does not conduct electricity. But its chief importance to us is that it’s elastic. When you stretch a rubber band and let it go, it springs back, to its original shape. Your rubber heels absorb shock when you walk because they have elasticity.

•Manufacturers use rubber to make everything from waterproof aprons, boots, raincoats, gloves, hats, automobile spare parts and tires, hair combs and doctors use it for hot water bottles, ice bags, syringes, elastic tapes and surgeon’s gloves. Hearing aids, oxygen tents and many other pieces of equipment have rubber parts. Infact, it has become an indispensable part of our life. It would be impossible to imagine life without rubber – for example, could you imagine the tires of a car made of any other material other than rubber? Literally thousands of products that we use and see everyday are made of different kinds of rubber. As rubber is really a dynamic and versatile element, it can be used to make almost any thing. Some of the common products that are made of rubber are: tires. baby toys, gloves, condoms, shock absorbers, watches, underwater equipment, garments, boots, rubber bands, car mats, machine parts, erasers and sporting equipments. The coefficient of friction of rubber, which is high on dry surfaces and low on wet surfaces, leads to the use of rubber both for power-transmission belting and for water-lubricated bearings in deep-well pumps.


QUESTIONS:

a. Name one important plantation crop except tea. Explain two important characteristics of plantation farming with reference to the crop named above.
Rubber.
Characteristics of plantation farming are:
Crop is grown on huge estates and plantation specializes in the production of one crop only.
There is a huge Capital investment and modern and scientific techniques are used.

b. State two geographical requirements for the growth of rubber.
Geographical requirements for the growth of rubber are:
RAINFALL – Heavy and well distributed rainfall throughout the year between 200 – 400cm.
TEMPERATURE – A constant high temperature of around 270C.
SOIL – Alluvial soil from which forests have been cleared is best suited for the growth of rubber plant. In India, rubber is cultivated on porous, well-drained laterite soil.

c. Kerala leads in the production of rubber. Give two reasons.
* Rubber is an equatorial plant .The climateof Kerala is similar to the climate of equatorial region.It
requires temperature ranging between 210C to 350C and 200 cm to 400 cm of rainfall. This type of
climate is found in Kerala.
* Porous, well-drained laterite soil is found in Kerala which suits rubber.
* It requires cheap labour which is available in Kerala.

d. When were rubber plantations first started in India? Why is rubber grown on flat or gently sloping land?
The rubber plantation were started in India by the British in 1902 on the banks of the river Periyar in Kerala,
· On flat or gentle slopes, machines can be used to clear the original vegetation.
· Gently sloping land also makes the tapping of latex makes easier for the tapper..
· On steep slopes soil erosion is a major problem but on flat land this problem is not there.
· Terraced farming on steeper slopes may add to the cost of rubber cultivation because the formation of terraces requires additional labour.

e. What is economic importance of rubber?
Natural rubber is sticky and very soft. Its properties can be improved by vulcanization. It is used in the manufacture of automobile tyres, tubes, soles of shoes, sports goods, foam rubber, mattresses and insulating material for wires and cables. In addition to it, it is also water-proof and air tight.

f. Name the tree which has become the exclusive provider of natural rubber. Why rubber is mostly produced in Kerala?
Hevea tree is the exclusive provider of natural rubber.
· Rubber tree grow best in areas with hot, humid and wet conditions throughout the year and requires temperature between 210C to 350C. All these conditions are found in Kerala.
· Rubber trees require heavy (more than 300cm) and well distributed rainfall. Kerala receives rain from south west as well as north east monsoons.

g. What are the two methods used in the propagation of rubber plant? Explain.
PROPAGATION BY SEEDS:
· Special germination beds are prepared and good quality seeds are germinated.
· Then seedlings are transferred to nurseries.
· Then these are planted in fields during the rainy season.

PROPAGATION BY BUD GRAFTING: Propagation by bud grafting is the best method of propagating rubber.
· After the seedlings have grown upto 5cm, buds from high yielding clones are grafted on to the seedlings.
· To establish the graft, it is bound to the seedling.
· Once the graft is established, the remainder of the old seedling is cut off just below the union.(tied point)

h. “Leguminous plants are grown between the seedling tree of rubber plant”. Why?
* Leguminous plants prevent soil erosion.
* These enrich the soil with nitrogenous compounds.
* These also supplement income of the cultivatiors.

i. What is tapping? What points should be kept in mind by a tapper?
Tapping is a process by which milk juice or latex is taken out from a rubber tree by making 2 mm deep cut at an agle of 300.
PRECAUTIONS:
· Cambium should not be damaged while making the cut.
· It should be done early in the morning when latex flows freely.
· It should not be done during rains.

j. Explain the processing procedure of rubber before marketing it.
* The latex is strained to remove impurities, coagulated into coagulum by the addition of acetic acid and formic acid.
* To squeeze out the water, it is then passed through rollers.
* To remove the excess water the wet sheets are then hung on reapers.
* The final drying of the rubber sheet is done in smoke houses.
* The sheets are then graded and packed in bales and marketed.

k. Name some of the items in the manufacture of which rubber is used.
Rubber is used in the manufacture of tyres, tubes, shoes, sports goods, cushions, mattresses, foam rubber, and insulating material.



l. What are the climatic requirements of rubber plantations in terms of: i) mean annual temperature
ii. Minimum temperature iii. Amount of rainfall iv. Rainfall regime
i. MEAN ANNUAL TEMPERATURE: 270C
ii. MINIMUM TEMPERATURE: 200C
iii. AMOUNT OF RAINFALL: Well distributed rainfall ranging between 200cm to 400cm.
iv. RAINFALL REGIME: Well distributed rainfall throughout the year.

j. What are ‘cover crops’ in rubber cultivation? Why are they grown?
Some leguminous crops are sown between the seedling trees of rubber to conserve the soil by adding humus and nitrogen content to the soil. The cover crops become the source of income for farmers until the rubber trees become mature after 7 to 8 years and starts giving income.

k. What is latex?
Latex is the sap of the rubber tree.

l. How is tapping done in rubber cultivation? When tapping is done and when not?
The process of obtaining latex or sap from the rubber tree is known as tapping. First, a cut is made about 1 to1.5 metre above the ground level and at an angle of 300 from the horizontal. The cut is made half-way around the circumference of the tree and slope down to the right. A zinc pipe is adjusted in the vertical groove through which the latex comes out.
Tapping is done early in the morning because in the morning the latex of rubber flows freely. Tapping is not done during rains as mixing of water may dilute the latex. Rubber trees are tapped between 200 to 300 days a year. A rubber tree gives latex from 25 to 30 years.

m. Why tapping is considered a skilled job?
Tapping of latex from a rubber tree is really a skilled job because a tapper has to make a cut which is only 2 mm deep. If the cut becomes deep, it will damage the cambium which is a paper-like thin skin between the bark and the wood of the tree.

n. Give the areas of rubber production in India.
Kerala, Tamil Nadu, Karnataka, Andaman and Nicobar Islands are the rubber producing areas of India. 91 per cent of the total area under rubber lies in Kerala alone.

o. Explain the bud grafting and name the crop associated with it.
In this process, bud of hjigh yielding plant is grafted into the seedlings of new plants combining the best quality of both.
Rubber is the crop associated with it.