Investigation on the effects of terrain slope and elevation on chemical features of wine within the PDO Prosecco area in Veneto region (Italy)

Abstract

The terroir can be considered as a well-defined area where natural conditions such as geomorphology of location, climate, ventilation, sun exposure, rainfall quantity and distribution, and humidity contribute to the production of a wine that is specific to that area and identifiable through the characteristics of the territory of origin (Bonfante and Brillante, 2022). However, microclimate could differ between vineyards within a region and depend on factors such as aspect, slope, altitude, and surrounding vegetation (Marais et al., 1999). For such a reason it could be possible to identify micro-terroir, or even more limited areas with more specific soil and climate conditions, even at a short distance from each other. For example, the side of a hill will not have the same amount of sunshine at the top or bottom, just as the temperature may be different, or even the water retained by the soil may vary due to the different slope (Strack and Stoll, 2022).

Based on these assumptions, the present work aimed at investigating the effects of different exposures deriving from the terrain slope on the phenology, chemical features of berries and wine, with particular focus on technological parameters and total abundance and intrafamily distribution of aromatic compounds. The goal was to identify possible sub-areas based on elevation within the Prosecco Superiore Hills of Conegliano and Valdobbiadene Controlled and Guaranteed Designation of Origin (DOCG), a macrozone in the Veneto region, Italy.

Six vineyards, Vitis vinifera cv. Glera, located in three different areas, each comprising hilly and flat sub-areas and characterized by different microclimate were investigated over a 3-year trial period (2021, 2022 and 2023) from budbreak to harvest in order to detect differences in production traits, phenology and chemical composition of berries and wine among the different elevations within each location.

A metabolomics approach based on gas chromatography–mass spectrometry (GC-MS) was adopted to investigate the aromatic profiles of grapes and wine in different vineyards. An altitude-effect on phenology, production and metabolome, with particular regard to volatile terpenoids, norisoprenoids and benzenoids was observed, although to a different extent depending on the site; however, there is also evidence that in the present study differences among the vintages must be considered to avoid misleading terroir-specific effects with those caused by the growing season.

References

Bonfante, A., and Brillante, L. (2022). Terroir analysis and its complexity. Oeno One, 56 (2), 375-388. https://DOI:10.20870/oeno-one.2022.56.2.5448

Marais, J., Hunter, J.J., and Haasbroek, P.D. (1999). Effect of Canopy Microclimate, Season and Region on Sauvignon blanc Grape Composition and Wine Quality. South African Journal of Enology and Viticulture. 20 (1). https://DOI:10.21548/20-1-2223

Strack, T., and Stoll, M. (2022). Soil water dynamics and drought stress response of Vitis vinifera L. in steep slope vineyard systems. Agricultural Water Management 274. https://DOI.org/10.1016/j.agwat.2022.107967