Handbook for Irrigation of Wine Grapes in South Africa

FIGURE 5.11. Tufts of grass tied around grapevine trunks to prevent possible salt damage caused by saline irrigation water near Stampriet in Namibia.

5.4.6 RECOMMENDATIONS • Classification of irrigation water according to EC and SAR should be used as the basis for management decisions should saline water be used for irrigation. • Controlled leaching can be applied to limit root zone salt accumulation if soil permeability and irrigation system allow it. • Avoid pollution of relatively fresh water by first calculating what the salt content would be after it has been mixed with saline water. • There are no economically viable methods to desalinate or treat saline water for agricultural use. • Since salts may damage leaves, saline water should not be applied by means of overhead sprinklers. • Under a given set of climatic and soil conditions, the best strategy is to keep salts that could eventually end up in the soil to a minimum.

122 CHAPTER 5 – IRRIGATION WATER QUALITY