CAB129-37 — Page 140

Land-clearing

Page 140

73. The sequence and methods of land-clearing operations at Kongwa, although all the land did not require the whole of these operations, were as follows:

(a) Flattening

This operation was carried out with heavy tractors moving through the bush in echelon round a pre-defined area, starting at the outside and moving in ever narrowing circles. Tractors moved independently, with bulldozer blades attached and kept raised some two to three feet from the ground.

(b) Contouring and Windrowing

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Because of the necessity for water conservation and anti-erosion measures and the need for a line on which to pile flattened bush, con- tours were marked out at nine-foot vertical intervals, followed by wind- rowing, an operation in which all flattened bush is pushed by bulldozers

to the contour lines, thus leaving continuous strips of cleared land. (c) Burning

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Burning, prior to windrowing, was carried out on as many fields as possible. This lessened the volume of bush to be moved, and reduced the load on the tractors and speeded-up the windrowing operation.

(d) Stumping

Following windrowing, the removal of any stumps left in the ground was necessary and had to be conducted as a separate operation, since the stumps were, in the main, too big to be tackled by the equipment used for breaking up roots left in the ground.

At first, the angle dozer was used but later in the year it was found that another rooter performed a better job with less strain on both the tractor and the equipment. This rooter consisted of an adaptation of a ripper, having a flat, straight blade welded across the two outer tines and the whole assembly set back behind the extremity of the ripper main frame.

(e) Rooting

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This operation followed the stumping and was originally effected by use of a 3 tined ripper, the necessity for single or double ripping being governed by the varying soil conditions.

During the past year, rooting was for the most part carried out by a specially designed rooter. The success of this implement was limited since, through the abrasiveness of the soil in dry weather, the wear on the machines was rapid. In addition, the larger rooters placed a strain on the most highly powered tractors.

The most successful machine for rooting at Kongwa was found to be an American heavy duty disc plough, which was used extensively towards the end of the year. Nevertheless, the rapid wear of all moving parts (particularly the discs) was considerable, and created a spares shortage which made it impossible to keep all machines working.

(f) Raking

Another operation before ground could be handed over for agri- cultural purposes consisted of the raking together of all roots cut and brought to the surface by the rooters. This operation was performed by a drawn rake specially designed and built for the Corporation.

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