Rubber is obtained from the milky juice or latex of a tropical plant heave brasiliensis which grows wild in Brazil. Its seeds were brought to India from Para (Brazil) in 1876 by Sir Henry William. Its first successful planting was carried on by Marquis of Salisbury in 1895 along the hill slopes of South Kerala. Later on its plantation was also made in the Periyar valley in 1902.

Conditions of Growth

Rubber plant requires hot and humid climate. It grows well in temperature conditions between 25°C-35°C (not below 21°C). The rainfall of 300 cm, well distributed over the whole year, favours the plant growth. Long droughts are harmful to the plant. Rubber grows well on deep well-drained loamy soils rich in iron and ammonia. Generally hill slopes
up to 300 m of height (in Kerala 300m-700 m) are utilsed in rubber plantation. The crop also requires cheap and abundant supply of labour to collect latex and process it.

Plantation and Processing

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Rubber seeds are first allowed to sprout in river-bed sands. Then these are planted in nursery from where these are transplanted to plantations after attaining the length of 0.4-0.6m. Generally 470 plants are planted in per hectare of land. After 2-3 years the plant starts yielding latex. About one-third of the plantations are raised from clonally seedlings which yield two and half times more latex than those of ordinary seedlings.

To obtain latex the bark of the lower trunk of the tree is cut in spirals and zinc or iron spout is placed at the base of the each cut. Tapping is done in the morning (6.30 a.m.) when the flow of the latex is maximum. The latex is collected in buckets between 9 a.m.-l0 a.m. when flow stops. In general each tapper attends to 250 trees each day. Tapping is suspended during January-February for 4-6 weeks. The latex so collected is cleaned and mixed with acetic acid. After slow heating it changes into a coagulated soft whitish mass in 24 hours. It is rolled into sheets which are cleaned in fresh water, dried and sent to the market.

Yield

The average per hectare yield of rubber is 1592 kg which varies from 1635 kg in Kerala (high­est) at 610 kg in Andaman and Nicobar Islands. This yield is less than half of the average yield in Malay­sia. However, there has been more than five times increase in the per hectare yield between 1950-51 (2.8 qtl. /ha) and 1997-98 (15.1 qtl/ha).