SOIL PREPARATION

SPECIAL SOIL PREPARATION STRUCTURES

5

5.1 Ridges Ridging (also called mounding) is a soil preparation method for soils which cannot be prepared effectively through deep tillage or for waterlogged soils which cannot be drained by subsurface drainage. Ridging entails the hilling up of the topsoil to form a continuous elevated ridge on which a crop can be planted. This practice creates a larger root volume for exploitation over impenetrable subsoil or above water tables. In fact, ridging is a form of surface drainage, i.e . the removal of water from the land surface by means of ditches or other forms of man-made alteration of the soil surface. Ridging was practised in Western Europe since Roman times for cultivation of vegetables and agronomic crops. The aim was to drain wet soil and increase its temperature. However, since the implementation of subsurface drains, ridging has largely disappeared. 5.1.1 Soils considered for ridging A decision on suitable methods for soil preparation, including ridging, should always start with a thorough investigation of representative profile pits. Ridging should not be done on soils that can be effectively improved by deep tillage e.g. on well-drained soils (Hutton, Clovelly, Glenrosa, Avalon, Oakleaf), low-lying alluvial soils with textural layering (Dundee), and deep sandy soils, even if they have clayey subsoils.

PHOTO: J.E. HOFFMAN, STELLENBOSCH UNIVERSITY.

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