Defying Dry

The wet side of El Nino has made most people in North America and Europe forget its dry side. That's the continuing drought affecting Indonesia, Australia, and much of southern Africa.

President Clinton's recent trip to Africa understandably concentrated on economic needs, democracy, and trade. So TV viewers back home didn't see desertification (the spread of the Sahara and Kalihari deserts) and drought (affecting crops in Zimbabwe, Mozambique, and their neighbors).

For the moment, then, Americans' climate memory is still crammed with wet scenes (California mud slides and frost on Georgia strawberries) not dry ones (barely remembered Western drought and water rationing).

But, when we return to the latter, innovation may bring good news to drought-prone areas. The Nestl Research Center in Switzerland has discovered and patented a system for treating dry soils that dramatically conserves moisture for plant roots.

The technique involves a compound that is inexpensive (derived from sand), easily sprayed on surface soil by standard sprayers, cuts evaporation by 75 percent, resists penetration by weeds, and eventually biodegrades back to sand. The system lets rain, dew, or irrigation moisture penetrate. Then it prevents evaporation back through the treated layer.

There are three added benefits, if all works as trials indicate: (1) Irrigation water use may be cut in half. (2) Because less water is applied, buildup of harmful salts beneath the surface (a problem in California's hugely productive Central Valley) is reduced. (3) The treatment can be combined with application of another product from the same lab that curbs wind erosion and sand drifts.

A mere spray program may not anchor the vast Sahara. But it may help villagers who live in areas beyond desert perimeters - and, more dependably, those who live in drought-prone regions everywhere.

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