salinity, the concentration of salt (sodium chloride) in soils or irrigation water. Among agricultural crops, grapevines are relatively sensitive to salt injury. Salt in the rootzone affects grapevines in two ways: firstly, it is harder for the vines to extract water from the soil, and they may suffer from drought. Secondly, salt can be toxic in high levels in the vines’ tissues. When vines are irrigated by sprinklers with water containing excessive salt, or grown on excessively saline soils, leaves may be burnt, and in severe cases this leads to defoliation. Similar effects can occasionally be found in coastal vineyards affected by wind-borne salt. merlot vines are particularly susceptible. Saline soils are typically found in hot and dry climates where irrigation has been introduced. For example, salinity is seen as a potential problem for the inland irrigated vineyards of Australia, along the Murray–Darling river systems. and also in padthaway. The problem is also found in southern France, where there are 10,000 ha/24,700 acres or more of vineyards planted on ancient marine deposits. Salinity can be overcome by applying more irrigation water than the vines use, so as to leach the salt. Some vine varieties such as colombard are tolerant of salt, and there are rootstocks such as Dog Ridge and Ramsey which show some salt tolerance. Grape juice and hence wine can contain elevated sodium and chloride levels. These appear unaffected by variety, and to result primarily from sprinkler irrigation (which wets the foliage) with saline water. Wine from vineyards with saline soils may contain elevated levels of salt.
