The soil and the Etna wines

Andrea Vadalà · 8 April 2020 · News

Difference between soil and terrain

In the article The volcanic soil of Etna DOC wines, we have already discussed the concept of terrain as a fundamental element of a Terroir and how this is unique and characteristic in the Etna context. Although they are often used as synonyms, land and soil are not the same thing.

The terrain is everything that is present on the surface of the countryside. For example, deposits of detritus that are at the base of a slope, have nothing to do with soil, they are simply inert accumulations of land. The soil, instead, is the element resulting from the alteration of a rocky substrate, in which the weathering processes are not only physical or chemical but also biological. These processes are carried out by all the surface agents and micro-organisms, flora and macro-fauna that interact and contribute to the creation of the soil itself, that exist within or on it.

Soil is, therefore, a living and incredibly dynamic system, something that engenders, not something that just lays. So, it is a physical bridge between the inorganic world and the living world. The result of a process that began with the disintegration and alteration of crustal rocks that, through complex transformation processes, provides support for almost all plant life on our planet, including of course the wine vine. This process is called pedogenesis.

Soils of pyroclastic origin

The Etna volcano, with its enormous extension of about 1200 square kilometers is not entirely pedogenized. On the contrary, a large part of the portions of the volcano, especially at high altitudes, are barren and desert. It is not only the altitude that makes the presence of life difficult. Lapilli, volcanic ashes and all those materials that we can define pyroclasts, are quite tenacious in their continuous covering the surface of the ground. Consequently, they hinder the formation of soil.

Conversely, many lateral volcanic cones, which are definitively less recent than the summit deposits, are now completely colonized and often exploited as excellent agricultural land. Therefore, the possibility of pedogenesis on Etna doesn’t depend that much on the composition or the pyroclastic genesis, as instead the age of the soil itself.

An ancient soil of great enological as well as geological importance, composed of pyroclastic falling material, is situated in Contrada Purgatorio. This place is located on the south-west side of Etna where the Ignimbrites of Biancavilla Montalto stand out. Here, the winery Emilio Sciacca Etna Wine cultivates rows of Nerello Mascalese, Carricante, and Catarrato, in one of the oldest soils of the volcano.

Ignimbrites of etna Biancavilla Montalto
Overview photo of the vineyard in Contrada Purgatorio

Ignimbrites of Contrada Purgatorio in the southwest side of Etna

Going back to the end of the Elliptical Volcano system, between 18000 and 15000 years ago; Etna was then very different from what it is today and had a much more explosive character.

During that period, violent volcanic eruptions used to project huge overheated columns (around 1100 ºC) of lava and gas fragments into the sky. The pyroclasts remained in suspension both for the abundance of gas and for their own lightness (abundance of pumices); all these fragments, falling in very rapid flows, (speeds over 300km/h) weld together, forming the ignimbrites.
The emplacement of an ignimbrites’ blanket takes place very rapidly, to allow the flux to retain enough heat to cause the weld. It is assumed that the ground temperature was at least 800 ºC. The high temperature and the great abundance of fluids have contributed to the reddish coloration it has today. As a result, it now brings evidence of strong alteration and oxidation of the metals of which the soil of Contrada Purgatorio is rich.

The extension of this formation was much larger in the past; but in Contrada Purgatorio, the geographical and altimetric profile allowed this ancient soil to survive, instead of being covered by more recent lava, as happened in many other areas.

The soil of Contrada Purgatorio

The soil today is dusty because of the tenderness of the fine matrix that fixes all the variously sized and weighted fragments present. Here the presence of terraces, with ably built dry-stone walls, becomes fundamental because the friability of the soil is rather accentuated, and the alternation of very dry periods with violent rains does not help the agricultural context but contributes in an elegant way to the creation of one of the most peculiar wines of Etna.

Detail of the formation of the ignimbrites under a vines yarded terrace

il suolo piroclastico di contrada purgatorio
The pyroclastic soil of Contrada Purgatorio

In these areas, green manure crops, generally used to enrich the soil, can be very important both to combat the early erosion that a dusty soil can present and to retain water and moisture in the surface blanket and to promote the absorption of rainwater. These simple considerations clearly correlate the soil and the wines of Etna, passing through those viticultural aspects that always require study and commitment.

Soil conservation and protection have been the subject of European Union case law – final COM(2002) 179: Towards a Thematic Strategy for Soil Protection – which specifies the role that agriculture should play, i.e. “… an indispensable mechanism for preserving the organic quality of soils, promoting the preservation of the plant layer and avoiding desertification.

All agricultural activities must, therefore, aim to maintain and improve the fertility of the soil which is the foundation of life”.  Emilio Sciacca Etna wine was born embracing the philosophy of natural wine with a great sensitivity for research in the field of ecology and sustainability.

These articles of scientific divulgation are part of the company’s efforts to an increasingly transparent, attentive and sustainable approach in favour of conscious agriculture and therefore of the entire community.