Soil impact on vines and wines of Vitis vinifera L. cv. Malbec in a high altitude vineyard

Abstract

The quality of grapes and wines depends on the “terroir”, a concept that in the simplest sense refers to the effects of plant material, environmental factors and canopy management. Therein, the soil characteristics have been described as a key factor. In this study, grapevines and wines from two contrasting alluvial soils, rocky shallow (shallow) and sandy loam deep (deep), in the same vineyard and under equal management were evaluated. The experiment was carried out during 2015–2016 in a high altitude vineyard at 1450 m.a.s.l. Four soil maps were compared in order to select the sites, i.e. built by measuring soil electrical conductivity (EC) at 0.5 m and 1.5 m of depth, soil depth at 70 in situ observation points per hectare and a normalized difference vegetation index (NDVI). Then, maps were overlapped, contrasting soil areas were identified and plants were chosen, based on their vigor homogeneity. The selected plants were used to evaluate the plant morph-physiology during the growing season (n = 12) and to elaborate wines (n = 3). Deep soil vines presented 50 % more shoots and 105 % more fruit yield than shallow soil vines. Deep soil berries showed 7 % less soluble solids (°Brix) and 10% more fresh weight than shallow soil ones. Panelists significantly differentiated wines from the two soils on a triangle test and unique sensory descriptors were proposed to characterize them. Future evaluation of berries and wines chemistry will contribute in assessing the soil type impact on high altitude Malbec vines and wines more precisely.