New Worlds: Research shows desalinated H2O bad for some plants

Ben-Gurion University scientists have found that it lacks many essential plant nutrients.

By JUDY SIEGEL-ITZKOVICH
Water 224.88 (photo credit: Courtesy)
Water 224.88
(photo credit: Courtesy)
Desalinated water is a boon to Israel due to the deficit in rainwater and the continuing pollution of natural sources, but Ben-Gurion University scientists have found that it lacks many essential plant nutrients, and is more harmful than helpful in irrigating certain crops. The discovery by Dr. Alon Tal of the Jacob Blaustein Institutes for Desert Research on the Sede Boker campus of BGU and several other scientists was published recently in Science. While water experts had long thought that desalinated water's low mineral content was beneficial to crops, new research reveals that it actually damages plants like tomatoes, basil and certain varieties of flowers due to a lack of magnesium and calcium. According to the study, titled "Rethinking Desalinated Water Quality and Agriculture," if these crops are planted above ground or in sand, they suffer even more, as they do not receive supplementary nutrients from the soil. Tal, a world-renowned environmental advocate, and his university are known for their expertise in water technology, and has been very successful in growing a wide range of crops, including olives and wine grapes, using brackish (low-saline) water. BGU is also a pioneer in desert aquaculture, and reuses water from fish pools as well. "Desalinated water is essential for sustainable development in our region. Since agriculture is already beginning to use desalinated water, and as there are cost-effective ways of providing water for human consumption as well as water with the minerals which can nourish tomato and other critical produce, new standards need to be adopted immediately. The fact that Ministry of Agriculture scientists were on the research team is extremely important." Tal believes that "desalination is a technology whose time has come. Israel's ability to produce 1,000 liters of pure water for less than 55 cents suggests that old axioms about water scarcity need to be reconsidered. No rational person can now argue that the next war in the Middle East will be over water when for $150 million dollars yearly, we can already produce all the water presently in dispute between Israel and the Palestinians. And that price will surely come down. So by no means are we arguing against the use of desalinated water." THE NOSE KNOWS Some people are oblivious to the odor in a locker room, while others wrinkle their noses at the slightest whiff of sweat. Research by Prof. Doron Lancet and research student Idan Menashe of the Weizmann Institute of Science's molecular genetics department, which appeared recently in PLoS Biology , has shown that this difference is at least partly genetic. Our sense of smell often takes a back seat to other senses, but humans can perceive up to 10,000 different odors. Like mice, which boast a highly developed sense of smell, humans have about 1,000 different genes for the smell-detecting receptors in our olfactory nerves. In humans, however, over half of these genes have, over the past few million years, become defunct - some in all people, and others in parts of the population. Lancet and his team had volunteers sniff varying concentrations of compounds that smelled like banana, eucalyptus, spearmint or sweat, and noted the sensitivity with which the subjects were able to detect each odor. They then compared results with genetic patterns of receptor gene loss, and found that one gene (OR11H7P) appeared to be associated with the ability to smell sweat. When participants had two genes with disrupting mutations, they were likely to be impervious to the offending odor, while those hypersensitive to the smell had at least one intact gene. The scientists noted, however, that while having at least one intact OR11H7P gene might determine whether you can tell by the smell that your loved one has just come from the gym, this is not the entire story. Most women are slightly more sensitive to smells than men, and some individuals of both sexes are better or worse in across-the-board acuity. And environment also counts.