Agricultural issues

Why was this Cat D8 here? This photo was taken on Tanah Radjah Rubber Estate, East coast of Sumatra in 1951. After the economic cycle of a planting of rubber trees, Hevea brasiliensis, the area needs replanting. During WWll the Japanese occupiers opted to replant with Ricinus communis to obtain valuable castor oil. Apparently an excellent lubricant to be used under extreme temperatures and good for air cooled combustion engines. The upshot was, that those areas were neglegted after the war ended and became quickly infested by what was commonly known as lalang, Imperata cylindrica . It formed a mat of rhizomes, two to three feet deep, locking up all nutrients and competing with any other crop.

One way of trying to get it under control was by ploughing it and establishing a cover as fast as possible, as it requires direct sunlight to thrive and for the seed to germinate.

In Asia the lalang flowered and formed seed, but for some peculiar reason it did not do so in Nigeria - at least not to the extent to have to worry about it. Its spread was mainly vegetative through its rhizomes. That is why on Utagba Uno Rubber Estate, Mid West of Nigeria the Caterpillar D8 was called "Old man Julius Obodo", whose sole job was to find small pockets of lalang, dig those out and dry out the rhizomes on tripods made of sticks.

The D8 on Tanah Radjah was later replaced by two Caterpillar D2’s using just disc harrows to the same effect. The lalang was so high, that on the very first day the D8 was off-loaded to the abandoned compound of an assistant’s house, the driver did not see an old well. Because of the size of the well and the fact that the soil was soft, the D8 itself needed extracting and that with all the high brass in attendance.

An effective cover crop used was Pueraria montana var.lobata known as Kudzu. For some reason I knew it as Pueraria japonica, but I stand corrected. Incredibly invasive as well and costing big money in keeping it under control during the immature stage of the planting. Left to its own devices it would climb and smother the young trees.
Centrosema pubescens was easier to control but harder to establish.

The cover crops also had the useful effect of nitro fixation , where the plant lives in symbiosis with nitro bacteria, forming nodules and introducing nitrogen into the soil.

This leads me to another very invasive plant - Siam weed. If you would like to read about that and matters to do with shift cultivation, erosion control and deforestation, look at the page called Agricultural issues two .

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