a history of South African soils
The traditional South African vineyard areas are located mainly along the coastal zone and toward certain inland areas of the Western Cape Province of South Africa. The soil in these areas has been identified as some of the oldest wine-growing soils on earth.
This landscape is characterised by pre-historic geological formations that are today still clearly visible due to sustained tectonic uplift (probably due to a hot plume of mantle rock below the southern and central part of the African continent) and subsequent erosion, resulting in steep, folded mountains that roughly parallel the coast, with younger deposits found in the high laying inland areas. The oldest rocks are the Malmesbury group (pre-Cambrian Namibian Epoch, 980-830 million years) of shale, phyllite, schist and greywacke, that occur in pockets as foothills and lower laying undulating hills around the Cape Winelands.
The other major geological development in the winelands occurred during formation of the Cape Supergroup. Here rocks were laid down as sediments in a rift valley that developed in southern Gondwana, just south of Southern Africa, during the Cambrian–Ordovician Periods starting about 510 million years ago, and ending about 350-330 million years ago. An 8-km-thick layer of sediment, known as the Cape Supergroup accumulated on the floor of this rift valley. Originally deposited in a flat-lying, shallow marine environment, the sandstones were subsequently folded during the formation of the super continent Pangaea some 300 million years ago.
This has resulted in the soils of the Cape Winelands being of ancient origin, with geographical influences spanning hundreds of millions of years resulting in soils that are geological marvels. Seriously Old Dirt.
the relationship between soil and wine
Soil is one of the most important aspects in nature, one which is essential for the existence of natural eco-systems and humankind. Soil, together with climate, is also the most important foundation of agriculture, and in winegrowing, it is paramount. Because of the diversity of soil profiles found throughout the winemaking world, soil can be one of the dominating factors determining the structure, flavour profile and character expressed by a vine. Along with climate and aspect, soil contributes to the very soul of what is in the glass. Just as the vineyards are rooted in soil, so too is the expressive identity of each wine rooted to the soils in which the wine originates.
The vine needs soil, water, sun and air to survive. The nature of each plays a profound role in the quality and personality of the end wine made from these vines. The roots of the vine are probing, living things, delving deep beneath the earth and into the soil to seek – as all living things do – sustenance. Water and nutrients can only be absorbed by the roots from the soil in which the vine grows.
Here the role of soil is all-determining, vital. Old, depleted, nutrient-deficient soils will cause roots to work harder and delve deeper to seek the moisture required to feed and sustain the vine. Seeking water and nutrients, these energy-sapping activities induce stress in the vineyard. Stressful conditions can make for hardy vines that produce lower yields, grow smaller berries with intense concentrated flavours that are reflected in the wine.
Roots do not carry flavours from the soil into the vine. However, soils can have a marked influence on the ability of the roots to absorb nutrients and moisture which contribute to taste, texture and structure in the final wine.
