A) Plastic Plastics are manufactured through the combination of several different compounds obtained chiefly from…
RUBBER (Hevea braziliensis)
Rubber is the only popular latex crop which produces white sticky liquid used in plastic industries. It belongs to the plant family, euphorbiaceae.
Land preparation: The land is cleared, stumping is done and the land may be levelled or it can also be done by ploughing and harrowing.
Varieties/Cultivars: PB86, Dough garden, BD5, Harbel 1, PB5/51.
Climatic and Soil Requirements: Rubber requires a temperature of 24°C to 29°C, rainfall of 180cm – 300cm per annum, bright sunshine and a deep loamy soil which is rich in humus and slightly acidic.
Method of propagation: By seeds and budded seedlings (vegetative propagation).
- Pre-nursery: August October.
- Nursery: nine months later.
- Budding: February – April.
Field: March – June the following year.
Spacing: Pre-nursery: 3cm x 3cm, Nursery: 60cm x 60cm.
Field: 4m x 6m.
- Place viable seeds in fertile top soils and water much heavily.
- The seeds germinate after seven to ten days.
Nursery: The seeds are planted on a rich fertile soil at a spacing of 60cm x 60cm. Mulching and watering (morning and evening) are done. Budding is done at this stage. Weeding should also be done.
Planting: The seedlings are transplanted to the field around March to June during rainy season. It is transplanted with a ball of earth on the roots and placed in a hole which is about 15-30cm deep.
- Weeding: This should be done regularly.
- Mulching: This should also be done, especially at the early stage of transplanting.
- Pruning: This ensures better aeration and good cultural operations within the farm.
- Planting of cover crops: This prevents erosion, evaporation and adds nutrients to the soil.
Maturity period: It takes three to six years after planting.
Harvesting: The process of harvesting rubber i.e, collection of the latex is called tapping. A diagonal cut is made 60cm above the ground on the bark of the tree with a tapping knife. The latex is collected with a cup below. Tapping is done early in the morning between seven to 10am and for every two to three days. The latex from all the cups are collected together from all the rubber trees in the evening.
Tools and materials required for tapping are tapping knife, spout, collecting cup, cup hanger, collecting buckets, churns, collecting tanks, anti-coagulants, e.g ., sodium sulphate or ammonia.
Processing of Rubber: The latex is collected in processing tank. A little water is added to dilute it. Formic or acetic acid is added to effect the coagulation of the latex. Then the coagulated latex is cut into pieces; washed and put into rolling machine to get thin rubber sheets. The rubber sheets are then washed and treated with paranitrophenol solution to prevent mould growth. The rubber sheets are dried and put in a smoke house for further drying so that ribbed smoke sheet (R.S.S) rubber is produced. Talcum powder is applied to prevent the rubber sheets from sticking together and for proper storage.
The rubber sheets produced are either purchased and sent to the port for export, or to the factories (e.g. tyre, plastic industries) where further processing into foams, shoes, pillows, buckets, mattresses, spoons, carpets, cups, plates, etc are carried out.
Pests of Rubber
Mealy bugs: These insects are vectors of diseases.
- Spray with insecticides.
Diseases of rubber
1) Tapping panel disease: It is caused by a fungus. It attacks the tapping panel, especially during humid weather condition.
- Disinfect tapping knife.
2) White and red rot diseases: They are caused by fungi. Affected trees produce yellow leaves which rapidly drop and the whole plant may die.
- Weed regularly.
- Diseased trees should be felled and destroyed.
- Spray the trees with copper fungicides.