Sunday, May 22, 2016

Overview of the soils of Sicily

I recently made a visit to the eastern portion of Sicily and will be writing a number of posts on the wineries visited. I will intersperse the discussion of the wineries with details of the physical environment within which they operate. I begin in this post with an overview of the soils of the broader Sicily, drawing heavily on the scholarship of Nesto MW and di Savino (The World of Sicilian Wine).

According to Christopher Bargman (Geology and wine in South Africa, Geoscientist 15(4), April 2005), soil is the major influence on the growth of the vine plant as it provides: (i) a supply of water; (ii) anchorage in the ground; and (iii) a source of nutrition.  According to, " soil is more than just dirt."  It is, instead, "... a complex system of decomposed rocks that have been enriched over time by decomposed organic matter."  Nesto MW and di Savino see soil as being "composed of varying proportions of parent rock eroded in place; material transported by gravity, wind, water, or glacial activity; and organic material deposited in place or similarly transported." The classic soil profile is shown below.


According to Nesto and di Savino, Sicily is 15% flat, 60% hilly, and 25 percent mountainous, a situation precipitated by the slow contraction of the vast ocean lying between the land masses of Africa and Eurasia. This contraction, especially over the past 50 years, has pushed up the cretaceous limestone seabed -- formed by a mixture of mud, skeletons, and shells of marine organisms deposited over eons -- to form the mountains and hills that we see today. The below figure summarizes the distribution of parent rock and soils on the island while the table following details the characteristics of the differing soil types.

Soil Type
   Everywhere except northeast      corner and on some volcanic islands
  • Enhances water-holding capacity
  • Soils white or pastel and reflect light
  • Cooler than darker soils
  • Vines tend to produce wines that are paler, more aromatic, higher in acidity, lower in tannins
  • Suited to white wines
  • If leached from limestone, the iron oxide residue tints the soil red (terra rossa)
Offers soil few nutrients
  • Etna
  • Hyblaean Mountains
  • Aeolian Archipelago
  • Pantellaria
  • Soil particle size range from dust to rocks; sand predominates
  • Rock types include pumice, lapilli (smaller particles of black volcanic rock)
  • Tuff (hardened volcanic ash)
  • Rich in micronutrients
  • Usually very porous and allow easy exploitation by vine roots
  • Inhospitable to phylloxera 
  • Like clay soils, allow high degree of physiological development in grape skins
Poor in macronutrients nitrogen and phosphate

  • Relatively rare
  • Some shaly schists in Nebrodi
  • A complex mix of calc-shists and paragneiss (a harder foliated rock) in the Peloritani
  • Can store water between foliations for vine root access
  • Can quickly decompose into sand, clay, or silt

Derived from Nesto MW and di Savino

©Wine -- Mise en abyme

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