Wired Greenhouses May Help Beat Droughts

Someday down the road water may become so scarce in America's Southwest that it will be more valuable than oil, and that has unleashed a flurry of activity among scientists who think the best way to save water may be to do away with the soil.

Hydroponic farming, in which nutrients are fed directly to the roots of plants which never touch dirt, isn't new. But modern technology has spawned a mini-revolution in its development and that could have a profound impact on regions around the Earth.

Examples abound.

This year, researchers in Antarctica are harvesting their own salads in an outpost that is 9,000 feet above sea level and so isolated that fresh vegetables were little more than a distant memory for workers in Antarctica in past years.

Near Baltimore, Alfons Casteel has tomato plants that are 25 feet tall, serving the agricultural needs of communities around his hydroponic greenhouse. Other hydroponic farmers across the country tell similar stories, although not everybody is successful.

And down near the border between the United States and Mexico, scientists are experimenting with using hydroponic technology to grow feed for cattle threatened by a persistent drought that has left ranchers high and dry across much of northern Mexico and the southwestern United States.

Water as National Security

What may be at stake here is an answer to a question that has plagued experts from CIA spooks to farmers: How are we going to head off potential water wars as water becomes increasingly scarce and populations continue to grow in regions where rainfall is a mere pittance of what will be needed?

"I view this as a national security issue," says researcher Ron Pate of Sandia National Laboratory, who is heading up the experimental greenhouse near Santa Teresa, N.M., where forage crops are already being harvested only 10 days after they were planted. "Disputes over water are possible, if not likely, causes for war in the 21st Century," Pate maintains.

Pate knows something about farming. His dad was a cotton and alfalfa farmer in Arizona for years, so after Pate earned his degrees in applied physics and electrical engineering he returned to his roots. Although Sandia is not all that much involved in agricultural issues, it's big in sensors, especially for the Pentagon, and Pate and his colleagues thought there ought to be a way to make the best of both of those worlds.

What came out of all that is a collaboration between several institutions in the development of a high tech greenhouse at Santa Teresa, near El Paso, Texas, to see if they could grow crops for livestock efficiently and economically. Joining in that effort are scientists from Mexico who have built a number of similar greenhouses for ranchers in the northern Mexico state of Chihuahua. Ranchers are running out of food for their animals in that increasingly parched region, now in its fifth year of drought.

Why such an effort? The numbers speak for themselves.

"Preliminary indications are that hydroponic greenhouses in New Mexico, for example, could reduce the current 800,000 acre-feet of water to 11,000 acre-feet to produce an equivalent amount of livestock forage," according to a statement from Sandia. There are about 260,000 acres used for growing alfalfa in New Mexico alone, and the scientists think they could produce just as much with 1,000 acres of greenhouses. That's an enormous savings of both land and water, especially considering the fact that more than 80 percent of the water used in New Mexico goes to agriculture, mostly for food for farm animals.

The key to the concept is something called "network sensing," and it was developed primarily with funding from the Pentagon's Defense Advance Research Projects Agency, which underwrites all kinds of cutting edge research.

Wired Crops

"This is a touch, feel and see kind of sensing capability," says Pate, and the Pentagon's idea behind it was to built a network of autonomous sensors that could talk to each other and relay data on their own in the search for things like chemical weapons. The research led to the creation of several companies that have begun manufacturing systems for commercial use, and the Sandia team seized the moment.

The researchers are using a network of 42 wireless sensors that sense light, temperature and humidity in the Santa Teresa greenhouse, telling them constantly of the health and needs of their plants. So far, it has worked pretty well, but as Pate puts it, the system "isn't quite ready for prime time yet." The plumbing system wasn't up to par, introducing mold that spread quickly through the closed environment, and now that system is going to have to be reworked.

But the greenhouse produces crops that can be harvested in 10 days, although at this point they leave much to be desired. Animal nutritionists at New Mexico State University who are analyzing the crops find that they contain far too much water.

"It's got about 80 (percent) to 90 percent water, which is way high when it comes to feeding a cow," Pate says.

It's also not as nutritious as it needs to be, but the researchers have come up with a creative way of addressing that problem. The plants are currently grown in trays that have to be washed and cleaned, so why not develop trays that can be eaten by the animals? Additional nutrients, and good stuff like fiber, could be included in the material used to make the trays.

That way, the cow can eat its lunch and the box it came in, reducing the workload for the farmers and insuring that the animal gets all it needs for a happy life.

At this point, no one is saying that hydroponic farming is going to solve all our problems. It's an expensive, high-tech operation that will require skilled technicians. But it could solve some major problems down the road.

Most of the water used for agriculture is wasted through evaporation, or soil saturation. And there isn't much incentive to change that because water is still pretty cheap and the underlying philosophy is "use it or lose it," Pate points out.

But someday that's going to change.

Lee Dye’s column appears weekly on ABCNEWS.com. A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.

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