BEER-SHEVA, ISRAEL - The news that olives are sources of "good fat" has increased worldwide demand for the luscious, versatile fruits. Olives have become extremely popular, enjoyed as condiments, appetizers, spreads, and additions to salads and sauces. Their heart-healthy oil has is also enjoying superstar status in kitchens around the world.
The olive's reputation as a health food is being borne out by modern science, as studies of olive-consuming Mediterranean peoples have shown. To keep the world's olive lovers satisfied, an intensive wave of olive planting has occurred in the past decade in many parts of the world. Traditionally, olives have been cultivated in the Mediterranean region. But fresh water is becoming increasingly hard to come by in semiarid areas, and irrigation of most new olive plantations is often accomplished with low-quality sources of water that contain relatively high levels of salt.
The relationship between the use of "saline water" and olive cultivation has been actively studied for many years. According to Professor Zeev Wiesman, Department of Biotechnology Engineering at Ben-Gurion University of the Negev, it is well-known that saline conditions can limit the development of olives, mainly because the salty water interferes with the olives' root system and causes "toxic accumulation of chloride and sodium ions on the leaves."
Weisman and other researchers recently published the report of a long-term study in which they established a new saline irrigation controlled experimental olive plot. The plot was planted with 12 local olive cultivars as well as olive varieties from Mediterranean countries, then divided into identical subplots: one irrigated with tap water, the second with moderate saline water. "In the study, we aimed to evaluate and compare the vegetative and reproductive multiannual response of mature yielding trees of the 12 tested olive cultivars drip-irrigated with tap water and moderate saline water in a commercial orchard simulation study in a semiarid area", stated Weisman.
Olive trees in both subplots were evaluated for trunk growth, olive yield, oil percentage, olive oil yield, and other characteristics. The data clearly showed a significant difference between the tested cultivars in terms of growth, yield, and oil parameters. Researchers concluded that all the tested olive varieties could be cultivated with moderate saline water irrigation. Weisman added: "Although a significant variation in terms of horticultural performance was found between the various tested olive cultivars, the differences may be attributed to the natural characteristics of each cultivar or to their rate of adaptation to the environmental conditions in the tested area, rather than to moderate saline drip irrigation."