Contribution of soil elemental contents and Cu and Sr isotope ratios to the understanding of pedogenetic processes and mechanisms involved in the soil-to-grape transfer (Soave vineyard, Italy)

The effect of soil on wine composition and flavor is controversially discussed in viticulture. Mineral nutrition of the grapevine is one possibility for an influence of soil chemistry on winemaking. However, effects of soil chemistry are difficult to isolate from other physical and biological factors. Here two winegrowing plots in the Soave region (Italy) were investigated, lying side by side on contrasted soil types. Factors that influenced soil formation and characterize soil chemistry and mineralogy were determined. The influence of soil type on the elemental composition (Mg, Al, P, S, K, Ca, Mn, Fe, Cu, Zn, Sr, Mo and Ba) of leaves and grapes was studied. Carbon isotope ratios were measured to evaluate water stress. Radiogenic Sr and stable Cu isotope ratios were studied to identify the influence of different bedrocks and better understand the mechanisms involved in the soil-to-grape continuum. Even though the morphology of soils is different, chemical characteristics are similar in both vineyard plots. Nevertheless, Sr isotope ratios of horizons of both soils show influence of different bedrocks on their genesis. The composition of grapevine plants is similar between both plots even though there is a tendency for higher elemental contents on more calcareous soil. Finally, isotope ratios show that different mechanisms control Cu and Sr in plant: Cu seems to be controlled by regulation mechanisms of the plants whereas Sr is absorbed in ratios similar to the soil, reflecting the different geological origins.