Soil salinity inter-relationships on chloride and potassium concentrations in grape juice and wine in the Mendoza River basin, Argentine

Abstract

Important vineyard irrigated areas of Mendoza show salinity problems. Wine chloride concentration in Argentina is legally limited to 0.6 g/L expressed as KCl. The industry believes that high Cl^– and K⁺ found in wines are due to vineyard come from saline areas and high K content in soils. During three growing seasons leaves, soils, juices and wines from different varieties and saline areas of the Mendoza River basin were analyzed to study the relation between soil, plant, and wine ion content. Petiole Cl^– concentrations at harvest were below 1% considered toxic in grapevine. The highest Cl^– concentration was found in Cabernet Sauvignon while the lowest in Bonarda. Chlorides in juices and wines were above legal limits in Cabernet Sauvignon, Tempranillo and Pedro Gimenez, and below in Malbec, Bonarda and Criollas. Shiraz duplicate the Cl^– concentrations during winemaking up to 1 g/L. No relation was found between juice and wine Cl^– concentrations. Chloride wine concentration was poorly associated to soil electric conductivity (r = 0.55, p ≤ 0.0015). Malbec skin and pulp Cl^– concentrations were higher than those in Cabernet Sauvignon. Conversely in wines, Cabernet Sauvignon showed higher Cl^– concentrations than Malbec (0.46 g/L). These varieties have different skin:pulp ratio and possible different extraction during winemaking. No relation was found between soil interchangeable K and wine K (r = 0.29, p = 0,105). The variety had influence on K juice and pH wine. This information is important evaluate in advance in saline areas, which varieties might have finished wines with ion concentrations above legal or commercial limits.