Salinity effects on vines and wines

Abstract

The electrical conductivity of irrigation water used for grape production in Australia is generally in the range of 0.2-3.5 dS/m, with most under 0.6 dS/m. Trials in the Sunraysia region have shown that moderate to high salinities (1.75-3.5 dS/m) over four seasons reduced yield of own-rooted grapevines (cv. Sultana) whereas vines grafted to salt tolerant rootstocks e.g. Ramsey experienced no yield reduction. Rootstocks such as Ramsey, 1103 Paulsen, 140 Ruggeri and 101-14 resulted in lower concentrations of chloride (Cl –) in Shiraz grape juice relative to own-rooted vines but some rootstocks e.g. K51-40, resulted in high grape juice and wine Cl– and sodium (Na+) concentrations when irrigated with water having a salinity of 2.1 dS/m. There is evidence that the Cl– exclusion ability of Ramsey and 1103 Paulsen decreases over several seasons of irrigation with 2.1 dS/m, whereas that of Ruggeri 140 is maintained. Comparison of Shiraz wine from vines on K51-40 rootstock, showing salt damage (“leaf burn”), with wine from vines on Ruggeri 140 rootstock with no visible “leaf burn”, showed no difference in wine colour density, total phenolics, total and ionised anthocyanins. Sensory assessments revealed statistically significant and substantial differences among the wines made from six rootstocks in “salty” ratings which correlates (r > 0.94) with the Na+, Cl– and potassium (K+) concentrations of the wines. The study shows that wines with unusually high ion concentrations can result from vineyard factors as distinct from winemaking practices, and highlights the negative impacts of high ion concentrations on wine quality.