A post about soil
Posted on November 5th, 2012
Soils are highly varied and often several different types occur within a single vineyard. Soil texture and structure depends on the clay content, which binds particles together and determines how water is retained or drained.
Excess water will cause vines to drown, whereas too little water will cause the vines to die of thirst.
Too much clay causes the soil to compact when it experiences pressure – vine roots only develop in non-compacted soil areas.
In very sandy soils roots may only develop where they find water (e.g. drip irrigation) and not make use of the entire soil volume available. An evenly spread root system is required for optimum plant health.
The organic and mineral content of the soil feeds the vine; however rich soils can cause excessive growth and mediocre fruit. Low-fertility soils with a good structure and drainage are preferred.
The three most important soil types in viniculture are sandstone- derived, granite-derived or shale-derived.
I’ll write a post about the principal soils found in South Africa later in the month.