Summer dry weather conditions mean that some vineyards are showing damage from salt (sodium and chloride). As soil moisture reduces vines pull water harder from the soil (plants create a negative pressure from the leaves to the roots - pulling harder means a higher negative pressure).
As the vines pull harder they take up more salt with the water. Eventually the concentration in the leaves becomes toxic and the leaves 'burn.' Sodium and Chloride levels in the developing fruit also increase which can have a detrimental effect on wine quality. Vineyards in the Langhorne Creek region are suffering from excessive uptake of Sodium and Chloride into their fruit.
Salinity in the vineyard can be measured by:
• irrigation water - amount of dissolved salts, electrical conductivity (ECe) and sodium adsorption ratio;
• the soil - salinity and exchangeable sodium percentage; and
• the vine - sodium and chloride levels in the fruit.
Look for leaves that are small, curled downwards and browned at the edges on most shoots of the vine (below).
|Salt uptake causes damage to leaf margins.|