The rubber tree species whose scientific name is Hevea brasiliensis is a native rain forests of the Amazon region of South America, including Brazil, Venezuela, Ecuador, Colombia, Peru and Bolivia.

These trees are generally found in low altitude moist forests, wetlands, riparian zones, forest gaps and areas which are not disturbed by human activity.

Background

These tree species were introduced to Southeast Asian countries during the 19th century and have been adopted by farmers in countries such as Hawaii, Brunei, Myanmar, Cambodia, Indonesia, Laos, Malaysia, the Philippines, Thailand and Vietnam among others as business initiative.

Rubber trees can grow to a height of 18 to 39 meters and they grow best in warm and moist climate ranging from 21-35 degrees centigrade with an annual rainfall of 80-120 inches or 2,000-3,000 mm.

Experts consider the plant as a tropical tree crop which is mainly grown for the industrial production of sap.

Like oil palm it requires a high and all year round rainfall with little or no dry season and stable high temperatures where soils should not be particularly rich but must be deep and well drained.

Farmers engaged in growing the plant usually drain its sap which processed into Rubber

Rubber is the major industrial product derived from the sap from a number of trees belonging to the genus Hevea species.

The bark of these trees contains a network of interconnected vessels through which the sap flows when opened.

The sap is a suspension of rubber particles which have to be coagulated to obtain the rubber. About 90% of the total world production of natural rubber is obtained from H. brasiliensis species.

Currently, natural rubber on the world market is competed by synthetic rubber, which is derived from oil products.

Africa and Ugandan case

In Africa farmers growing the plant are from Liberia, Nigeria, Democratic Republic of Congo, Mozambique, Madagascar and in Uganda it is grown at very low rate mainly as ornamental.

According to a report by H.N Whiteford and Alfred Anthony from the US special agent department of Commerce, they stated that in early 1990’s Africa was rated second in growing rubber trees after South Africa.

The production fell due to World War I in 1914 due to lack of export market

In Uganda the places where the trees can be spotted are at the Botanical Garden in Entebbe where the first explorers brought various species of plants all of which were planted there for further testing in various parts of the country.

There are places such as Golf course club, Makerere University, Sheraton gardens and Constitutional Square among others were rubber trees can be spotted.

According to available records there is a Uganda businessman, Robert Giffen Kamulidwa, who leased one square mile of a rubber plantation in Bujenje County, Masindi district, to produce smoked rubber sheets.

The owner of the abandoned rubber plantation wanted to turn it into sugarcane plantation but he persuaded her to lease it to his company Kibopi Estates (U) Ltd so that he could continue the production of rubber on the land.

The company is reported to be selling its rubber products to Bata Shoe Company Ltd. The company until now has been importing rubber materials from Thailand, India and Pakistan.

Agronomy

In a rubber tree production guide published in Dairy Business PH situated in Philippines, the publishers highlight various agronomic practices famers wishing to adopt growing of the tree including selection of good disease free varieties.

Varieties

The experts state that Rubber belongs to the family of Euphorbiaceae, a large family with about 280 genera and 8,000 spp species.

The most common genus Hevea class is widely adopted and it exhibits much morphological variability with nine species now being recognized, ranging from large forest trees to little more than shrubs.

All of them contain latex and other Hevea spp are tappedform the wild little economic value. Some of them may however be important as breeding: material for scientists to improve other varieties

These varieties H. benthamiana grown only north of the Amazon River in the north-western part of Amazon and Upper Orinoco basins in hydromorphic soils; it has a pure white sap which is lower in yield.

H. camporum is native to open savannas and this variety is well adopted in the African continent

Others are H. guianensis which can grow 30m high or more and prefers well-drained upland soils producing yellow sap, H. microphylla: endemic in uppermost Rio Negro basin in Brazil, Colombia and Venezuela with low yield, H. nitida which grows throughout most of the parts of Amazon, H. pauciflora, H. rigidifolia and H. spruceana which are all capable of growing in well drained soils.

Land and climatic requirement

Rubber trees grow well in plain well-drained soils with deep water table with soil pH of 4.0-6.5
The way a farmer tills the land must enable good aeration containing abundant organic matter

There has to be 80% atmospheric humidity with moderate wind speed, average rainfall of 2000mm evenly distributed throughout the year, bright sunshine and there is no distinct dry and wet seasons.

Land Preparation

Adequate clearing of the planting site is recommended to avoid competition for nutrients with weeds and second growth forest trees.

In flat cultivated areas, farmers are expected to plow the land twice before laying out.

In hilly areas, terracing is encouraged following the contour lines. And this must be done to prevent soil erosion.

Plant spacing largely depend on the topography of the area and the possibility of planting intercrops is possible with crops such as coffee or green vegetables.

Crop Establishment and propagation practices

Farmers are expected to select seeds that are fresh, big, heavy and shiny. Before sowing the seeds, they must be soaked in water overnight and 10 kg of seeds can germinate in every one-square meter of seedbed. Fine river sand or sawdust can be used as seedbed and with partial shade.

In sowing the seeds, they should be pressed firmly into the seedbed until the top of the seed is leveled with the surface, then cover the seeds thinly with the medium to prevent exposure to direct sunlight.

Water the seeds twice a day and in 10-14 days, the seedlings can be pulled and planted into polythane bags or in ground nursery.

Preparation of nursery beds

Land preparation should be done prior to seed germination. The area should be cleared and clean. The size of poly could either be 6 by 12cm in for young green seedlings with 1-2 leaves and 7 by 14 cm for brown seedlings with 2 leaves.

The perforated polythane bags are filled with loam soil and placed in a shallow canal arranged in east-west orientation with 2 polythane bags per row spaced 36 inches between rows.

In the absence of soil analysis, apply 10-15 grams of fertilizer per bag every 3-4 weeks.

Planting

Budded seedlings ready for planting have matured top leaf curls with healthy and vigorous appearance with dark green color.

The size and shape of the planting hole depends largely on the soil condition and planting materials. In fertile and light soils, holes should measure 25-30 cm in diameter and 40-45 cm deep.

In poor and heavy soils, bigger holes are required ranging 40-45 cm diameter and 50-60 cm deep. Further, if the land is currently being cultivated, smaller holes will do, but in uncultivated land, bigger holes are needed.

Tree management

Pruning must be done regularly to develop a smooth trunk without branches or large scars on the stem along the optimum height of 2.5-3 meters from the ground. This should result to the bigger tapping panel. Pruning of the top portion of the tree is not a recommended practice.

Nutrient Management

The first three years of plantation establishment is the most critical period where complete nutrition should be provided to the plant.

 Ideally, fertilizer application should be based on the results of soil and plant tissue analysis to ensure that the optimum amount is applied.

Whole, broadcast and ring methods of fertilizer application can be used and application is made at the start and before the end of the rainy season. Organic fertilizers can be used – with the rate of application based on the kind of organic fertilizer and recommendations made by experts.

Pest Management, disease and weed management

Weeds in rubber farms can be controlled by line weeding, slashing, round/ring weeding, and the use of herbicides.

Weeds in rubber areas must be controlled or minimized to prevent stunted growth of the rubber trees and to prevent fires during the dry season.

There are about six foliar fungal diseases of rubber which include bird’s eyespot, powdery mildew, leafspot, leaf blight, anthracnose algal spot which attack both the tree leaves and stems in some cases

Nursery diseases consist of seedling blight and tip blight which can be controlled by applying recommended chemicals

Harvest Management

Rubber trees are ready for tapping when the trunk circumference reach 75 cm from the stock- and when the scion union reaches 40-50 cm in circumference.

It requires around five year’s growth period under good management. Tapping should start on the 6th or 7th year after planting

Farmers are expected to cut the three truck and make a scion form which the sap can drip to an attached container which must be collected at any one moment and poured in a bigger collection container. Processing into rubber is done by the manufacturing industries.