Gravel soil

The soil composition of vineyards is one of the most important viticultural considerations when planting grape vines. The soil supports the root structure of the vine and influences the drainage levels and amount of minerals and nutrients that the vine is exposed to. The ideal soil condition for a vine is a layer of thin topsoil and subsoil that sufficiently retains water but also has good drainage so that the roots do not become overly saturated. The ability of the soil to retain heat and/or reflect it back up to the vine is also an important consideration that affects the ripening of the grapes.

There are several minerals that are vital to the health of vines that all good vineyard soils have. These include calcium which helps to neutralize the Soil pH levels, iron which is essential for photosynthesis, magnesium which is an important component of chlorophyll, nitrogen which is assimilated in the form of nitrates, phosphates which encourages root development, and potassium which improves the vine metabolisms and increases its health for next year's crop.

Unless otherwise noted the primary reference for this list is Sotheby's Wine Encyclopedia 2005

...
Wikipedia