SOIL PREPARATION

CHAPTER 5

Ridging can be considered when sub-surface drainage is not possible or when the topsoil is shallow and the subsoil cannot be loosened effectively by conventional soil preparation methods. Candidate soils for ridging include low lying wet soils with a shallow water table e.g. Katspruit, Westleigh and shallow (< 50 cm) duplex soils underlaid by impenetrable clay such as the Estcourt soil form (Figure 5.1). On shallow Glenrosa and Mispah soils, where the rock cannot be ripped loose because it is too hard or it will be too expensive, ridging will also provide a viable alternative. In its natural state, these aforementioned problematic soils are marginal for vineyard cultivation.

FIGURE 5.1: Shallow Sterkspruit soil on which ridging will be one soil preparation option for viticulture due to the heavy clayey, structured subsoil. The final choice of preparation method will, however, also be affected by the thickness of the clay layer and the nature of the underlying material (Photo: ARC Infruitec-Nietvoorbij). 5.1.2 Construction of ridges The construction of ridges for planting of a vineyard must comply with a few basic principles, namely: • Prevention of compaction by the wheels of the construction vehicles. • Creating a ridge height of 30-50 cm as measured from the top of the ridge to the ditch between ridges. • Creating a ditch wide enough to prevent vehicle traffic from driving on the slanting sides of the ridges. • The ideal ridge has a flat or slightly convex crest with relatively steep sides. Before ridging, vine rows have to be planned and pegged out. In practice, growers construct ridges by ploughing soil from the middle between rows to

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