What Effect Does Soil Have?
Most South Africa soils are not very fertile but this does not have to be a disadvantage. Rich soils can often produce over-vigorous vines, which means the grapes produced can have little complexity or character. Even so, we have three types of basic parent materials and each produces a different soil type.
The parent materials and the soil types they produce are (do a graph or something).
Granite: Tukulu, Hutton, Clovelly
Shale: Swartland and Glenrosa
Sandstone: Longlands, Fernwood, Estcourt
Soil classification is an intricate and specialised subject and we won’t go into it too much. We just need to point out that the criteria are organised according to the colour of the subsoil and topsoil, the presence and order of the various layers in the soil, the clay content, and lastly the sand fraction.
Good drainage can be recognised in soils that are red or yellow in colour, while dark colours which range from blue-black to dark brown can indicate poor to average drainage and could be due to a high water table. In these soils rust spots or white spots can indicate even further that the soils are waterlogged. White soils indicate that there is too much drainage and are seen mostly in sandy soils where nutrients and chemical compounds have leached away.
Water retention capacity is a term that is used to refer to the amount of water that is stored by the soil, and is a key factor in overall vegetative growth and fruiting capacity of South Africa’s vines.