Zonation of a Viticultural Territorial Context in Piemonte (NW Italy) to Support Terroir Identification: The Role of Pedological, Topographical and Climatic Factors

Grapevine production and quality greatly depend on site-specific features such as topography, soil, and climate. The possibility of recognizing and mapping local specificities of a wine-production area is highly desirable, as environmental conditions are the main drivers of wine production in terms of both quality and quantity. Areas showing similar features able to determine specific traits in vine and wine production are referred to as terroirs. It is commonly considered that soil and climate represent the main elements for a functional and balanced viticultural ecosystem; if they change, grapevine quality and yield change too, and this occurs in spite of any agronomic practice. Terroir mapping based on traditional methodology requires a considerable investment of time and money by producers and wine consortia; moreover, it preserves an important subjective component. In this work, the authors propose an approach to map territorial differences, possibly conditioning the definition of terroir, of an important wine-production area located in Piemonte (NW Italy) based on free and open data and free GIS. The resulting zones were related to the main local vine varieties looking for possible relationships. The results proved that, with reference to the pedological, topographical, and climatic factors, six zones were recognized as significantly different in the study area. These were compared against the six main vine varieties in the area (i.e., Barbera, Brachetto, Chardonnay, Dolcetto, Moscato Bianco, and Nebbiolo), finding that: (i) Nebbiolo is highly specialized, covering almost a single zone; (ii) Moscato, Dolcetto, and Chardonnay showed no significant preference for any zone, being almost equally distributed over all of them; and (iii) Barbera and Brachetto are averagely specialized, being distributed mainly over two clusters (out of six) different from the one where Nebbiolo appears to be majorly present.