Volcanic soil, complexity and longevity

Volcanic soil, complexity and longevity

Territories characterized by soils of volcanic origin are some of the most particular in the world.

 

They can have very ancient origins as in the case of Soave and Lessinia, areas located between the northern valleys of the provinces of Verona and Vicenza where the volcanoes went off between 25 and 50 million years ago. Or they may be more recent, as in the case of Santorini, the Greek island that is part of the Cyclades, in the Aegean Sea, which emerged about 2 million years ago and whose current soil rests on a lava crust brought about by the violent eruption of the Thera between 1627 BC and 1600 BC that produced a layer of lava rocks, ashes and pumice of at least 30 meters, covering the entire island.

 

VOLCANIC SOILS

Despite differences in origin, the chthonic (underground) material poured out on the surface presents similar characteristics, giving the products of these lands similar and well-identifiable qualities, rightly protected in Europe using PDO specifications, as in the case of Soave, Soave Superiore, Lessini Durello, Monte Veronese and the Santorini denomination, which identifies the wines and typical vegetables grown here.

Volcanic soils are often close to important tectonic faults, along the borders of which there can usually be found soil with heterogeneous chemical composition due to the vertical displacement of buried layers towards the surface. Similarly, there are also soils that have formed from underwater volcanic eruptions and are the result of the mixing of volcanic matrices with marine deposits, or those that originated from glaciers containing numerous erratic rocks and finer particles of volcanic origin.

 

Heroic viticulture and the human landscape

Volcanic slopes are often difficult to cultivate due to the hardness of the rocks or the unevenness of the terrain, which make the cultivation of these territories a valiant feat. Oftentimes, the winegrowing methods practiced here are the result of ages-old work of shaping the arable land by constructing manmade terraces and performing manual tilling that have transformed these landscapes into true works of art.

 

Soil composition

 The soils that are formed after eruptions and flows are therefore very heterogeneous. Lava brings deep rocks to the surface which are then dissolved in the basalts; but deposited above them are many elements of explosive origin like ashes, lapilli and volcanic bombs (drops of burning rock ejected from the cone of the volcano). Stratified pyroclastic materials may solidify over time and produce volcanic tuffs, which in the following stages of erosion form sandy, coarse soils, rich in mineral elements and skeleton. Whereas, volcanoes that are made up of cooled lava flow have more definite slopes and generate soils with dark colour, often superficial, tedious to transform into a type of soil apt for agriculture and rich in clay.

Even the stage of cooling, particularly the speed at which this occurs, has a strong impact on the structure of the rocks. If cooling happens slowly, intrusive rocks are formed, characterized by the presence of small yet visible crystals. But if magma resurgence is fast, and cooling occurs on the Earth’s surface, the solid mass is vitreous and the crystals are very small.

 

Chemically, the main element present in magma is silica (from 50 to 70%), followed by aluminium oxide, magnesium, iron, sodium and potassium oxides, and, in terms of reaction, they can be basic, acidic and neutral, depending on the content of silica.

 

The volcano “flavour”

The extraordinary heterogeneity of volcanic soils and the incredible mineral content that the lava layers supply are certainly some of the key factors needed to understand the relationship that man has established with these territories. Volcanic soils are also particularly rich in phosphorus, magnesium and potassium: this brings out natural products (especially wines) characterized by a certain complexity and sapidity that cannot be obtained with other types of soils, but it also endows them with great minerality, acidity and longevity.

Complexity and longevity are the characteristics that distinguish the PDOs promoted by the Heva – Volcanic Agriculture of Europe project: Soave, Soave Superiore, Lessini Durello, Monte Veronese and Santorini. Products that, although belonging to different categories (wines and dairy products), have something special thanks to the type of soil in which they grow.

This complexity translates into an intense, savoury, persistent, strong and by no means aggressive flavour, with different sensorial shades and nuances. Its longevity is expressed in wines with great aging potential and natural acidity that preserves freshness; as for the cheeses, it enhances development during aging as in the case of the Monte Veronese PDO d’Allevo made with Alpine milk, which is marketed after a year of aging.

Complex terroirs for exceptional products: the DOPs promoted by HEVA
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