Can the desert be made to yield more water, food and energy?
By Donald H. Harrison
SAN DIEGO –Scientists at the Sde Boker campus of Ben Gurion University of the Negev are making strides in their quest to make the world’s deserts more productive by increasing their yields of energy, food and water, Pedro Berliner, director of the Blaustein Institute for Desert Research told about 50 people Tuesday evening, Nov. 29.
In a 45-minute lecture at the San Diego Jewish Academy, Berliner sketched some of the projects Ben Gurion scientists are pursuing in an area of Israel that receives no more than 4 inches of rainfall annually.
Taking their cue from the ancient Nabateans, a migrant people who carried trade goods between the Arabian peninsula and the Levant, Ben Gurion scientists have helped develop artificial oases in the desert. Usually when it rains in the desert, the water comes down fast and hard, much of it flowing all the way to the sea without having a chance to be absorbed into the ground, Berliner said.
But after studying the routes by which the rain waters typically flow, the scientists were able to divert some of the rain into artificial ponds, around which they planted pistachio trees. Between the rows of trees are planted various ground crops, which can be fertilized by mulching the leaves of the trees. Branches can be used for firewood. And all this can be done naturally, without the use of expensive fertilizers, he said.
The Israeli system for diverting flood waters into artificial oases is now being used in the deserts of such countries as Kenya, Turkmenistan and Argentina, Berliner said, adding that Israelis consider it their moral duty to export their knowledge in order to help other peoples of the world.
Another food project involves cultivating algae from the brackish water that comes up from underground aquifers. This water is too saline for use with normal crops, but algae thrives on it, and in turn, fish raised in artificial ponds feed on the algae and grow bigger and more quickly than they do in other environments, Berliner said. Thus, he said, protein can be produced in marginal water extracted from marginal lands.
The algae has another use as well: it can be converted into an efficient biofuel. Unlike the corn of the American Midwest that is used for biofuels–but is taken away from an increasingly scarce food supply– the algae-generated biofuel does not subtract from the food supply, Berliner said.
Desalination is another area of concentration at Ben Gurion University, according to Berliner. Usually desalination involves either reverse osmosis, which is pushing dirty water through tiny holes in membranes, leaving behind the solids — or heating the salt water to the point of evaporation. Both processes require a lot of energy, making them quite expensive.
Berliner said Ben Gurion University is attempting to develop a method that utilizes solar energy and also permits the treatment of water at lower than usual temperatures.
He said university researchers also are working on developing methods to prevent the filters used in osmosis from becoming clogged with bacteria.
Another problem Ben Gurion researchers are addressing is how to prevent contamination of the ground water supply. Organic farming, using manure and other natural products, make this more complicated than farming using conventional fertilizers, he said. This is because it is not currently possible to know exactly how quickly composted organic material will decompose, resulting in surplus materials being leached into the groundwater supply.
He said scientists at Ben Gurion University are developing a method to calculate exactly the rate of decomposition of the various materials in the compost mix.
Dryland environmental research is another area upon which Ben Gurion scientists are concentrating, Berliner said.
One project is intended to concentrate solar energy for the more efficient use of photovoltaic cells, which can supply electricity to homes and to factories. A related effort is to find a way to use organic materials to produce cheaper photovoltaic cells.
Berliner said the scientists also are looking at ways to moderate desert temperatures in residential developments. This involves laying out communities in accordance with prevailing wind patterns and mapping precisely where gardens should be planted to help keep temperatures down. He said typically it is far more efficient to have rows of gardens between houses than to focus them in a central park.
The scientists also experiment with the use of overhead cover. Do trees, meshing, or some combination of the two bring more relief from the desert heat? Should communities plant more trees than lawns, given the fact that trees consume much less water than grass?
Berliner said these kinds of questions are important because “dry lands occupy 41 percent of the land area of the earth, and are home to 2 billion people.”
A major problem that Ben Gurion University is battling is the increasing desertification of the planet, with scientists trying to find ways to prevent areas that were once fertile from being transformed into deserts.
The desert research facility in Sde Boker has 85 faculty members who work with students at the master’s, doctoral and post doctoral levels, Berliner said. The language of instruction is English, and the program draws students from around the world.
In a brief talk preceding Berliner’s, David Siegel, Israel’s consul-general in Los Angeles, said that a night flight over Israel will show much of the Galilee and the Negev unsettled and dark, while the areas of central Israel around Tel Aviv and Jerusalem form a bright arc of light. He said this overcrowding in the center of Israel is “not sustainable in the long run” and thus the Israeli government is trying to encourage people to move to the periphery of the country–to either the Galilee or to the Negev.
Research at Ben Gurion University to reclaim the Negev for Israel’s growing population is important to that country’s future, as well as for the populations of desert countries around the world, he said.
Berliner was accompanied to San Diego by Prof. Amos Drory, who is Ben Gurion University’s vice president for external relations. Rabbi Arnold Kopikis, the university’s representative in the San Diego County area, started the evening’s proceedings with a short prayer for the welfare of Israel.
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