SOIL PREPARATION

CHAPTER 7

FIGURE 7.3: Implement set-up used in practice, namely a wing plough used in conjunction with ripper (left) (Photo: ARC Infruitec-Nietvoorbij) and delve plough mounted to draw power from the centre of the tractor (right); therefore no balancing tine needed (Photo: J.E. Hoffman, Stellenbosch University). The wing plough causes compaction in the form of a plough sole below the wings. Soil that flows over the wing will also be compacted, especially when the soil is still wet and does not contain gravel. In order to prevent such compaction, vertical steel plates (normally four) are mounted on the wings to shatter the soil. The use of a wing plough is mainly recommended for dry duplex soils such as Sterkspruit, Estcourt, Swartland and Glenrosa soil forms, in which case it not only loosens the soil, but also removes the sharp transition between topsoil and subsoil.

FIGURE 7.4: Wing plough (left) (Photo: ARC Infruitec-Nietvoorbij) and sketch of wing plough (right) with dotted lines indicating the flow path of loosened soil (Sketch: J.E. Hoffman, Stellenbosch University).

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