Estimating the impact of irrigation water salinity on vines in the Mendoza and Tunuyán river basins

Abstract

Studies on climate change impact on the South American Central Andes predict scenarios of reduced river flows and salinity increases downstream of the Mendoza and Tunuyán River basins and indicate that these impacts would lead to a reduction in crop yields. This paper shows that irrigation water salinity affects vine production. The objectives are twofold: to characterize water quality conditions in different parts of the basins and to assess their effect on crop yields. A database of physicochemical and microbiological quality of surface water has been created for both rivers. Eighteen sampling sites were selected, eight on the Mendoza River basin and ten on the Tunuyán River basin. The model that was used “Aguas de Riego. Calidad y evaluación de su factibilidad de uso” was developed by Avellaneda et al (2004) to calculate effective electrical conductivity and sodium adsorption ratio (SAR), among other parameters. Production variation on the basis of salinity was estimated with the equation proposed by FAO. Effective electrical conductivity values range between 0.25 and 1.76 dS.m^-1 which, according to Wainstein (Wainstein, 1969), belong to C2 (slightly saline) and C5 class (highly saline). According to Riverside (USSLS, 1954) extreme mean values of SAR of 0.39 and 2.49 belong to S1 (low hazard) class for all sites. It is concluded that yields in sites with highly saline irrigation water would be reduced by 19% (Mendoza River) and 16% (Tunuyán River).