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A patch of green

'My colleagues say I'm crazy. But it doesn't hurt to dream.'

October 14, 2009|By KAREN KAPLAN

In a parched experimental plot at the edge of UC Riverside, several dozen mounds of grass poke out of the powdery soil.

These plants have the soft, narrow leaf blades and dark-green hue that would make them a welcome addition to any American lawn. Most important, they lack the feature that threatens to doom today's turf: an unsustainable thirst for water.

With mandatory watering restrictions turning grass brown from California to Florida to Massachusetts, a small but dedicated cadre of turf scientists is on a mission to engineer a drought-proof super-lawn.

They are acutely aware of the technical challenges. Millions of years of evolution have failed to devise a turf that thrives in dry, hot summers and cool, damp winters, and trying to one-up Mother Nature certainly is an exercise in horticultural hubris.

Low water demand is crucial, but it's not enough. To have a shot at commercial success, the grass also would have to tolerate shade, be resistant to fungi and pests, grow at a relatively slow pace, produce ample seeds and pass down the same characteristics from generation to generation.

It could take years, even a decade -- if the effort succeeds at all. But as water becomes increasingly scarce, researchers say the need for less thirsty lawns is too great to ignore.

"Thirty years from now, it would be nice to say it really did pay off," said plant geneticist Jason Goldman of the U.S. Department of Agriculture, who has already invested five years in his efforts to create a super-lawn in Woodward, Okla.

With California mired in its third year of drought, UC Riverside turfgrass specialist Jim Baird has become another true believer. He hopes his water-wise prototypes will grow up to be the lawns, parks, golf courses and athletic fields of the future.

"My colleagues say I'm crazy," he said. "But it doesn't hurt to dream."

Appearance has always been the most important aspect of American lawns.

Wealthy homeowners began planting them in the 1700s as status symbols to evoke the manicured grounds of English estates. Only the upper class could afford to employ small armies of servants to keep grass trimmed to lawn-level height with hand-held blades.

That changed after the Civil War, when the availability of garden hoses and mechanical push mowers made it possible for regular homeowners to tend to their own lawns. Americans came to favor emerald-green grasses over the apple-green shades that are prized in England.

Today, about 50,000 square miles of lawns, golf courses and parks blanket the U.S., according to estimates derived from NASA satellites. That's enough to cover the entire state of Mississippi, with some to spare. Keeping all that grass green requires about 200 gallons of water per American per day, NASA scientists have calculated.

Water restrictions make such maintenance increasingly untenable.

As of June 1, the Los Angeles Department of Water and Power limited the use of sprinklers to 15-minute cycles on Mondays and Thursdays. Restrictions are in effect throughout California, as well as in Nevada, Minnesota, North Carolina, Florida and other states.

Turf experts recognize that something has to change.

"We need to convince people that in the summer you don't need to have a lush green lawn," said Bingru Huang, a turfgrass physiologist at Rutgers University in New Brunswick, N.J.

Baird, whose obsession with grass grew out of a teenage interest in golf, thinks Americans would sooner rip out their lawns than tolerate months of brown grass in their yards.

"We're trying our best to ensure we have some turf around," he said.

Grasses have evolved a variety of strategies for coping with drought.

Some grow deep roots that can reach water far below the surface. Some go dormant and turn brown, preserving their resources until rain returns and conditions are more favorable for growth.

Other plants accumulate sugars and related compounds in their stems and leaves to help them hang on to whatever water they manage to find.

And some minimize water loss during photosynthesis by growing waxy coatings or hair-like filaments that capture water vapor escaping through pores in the leaves. Warm-season grasses such as Bermuda and St. Augustine do a better job than cool-season grasses like Kentucky bluegrass and tall fescue of capturing carbon dioxide without losing water, Huang said.

Most Californians plant tall fescue varieties, such as Marathon, in their yards. They are the most water-efficient of the cool-season grasses, but that still leaves plenty of room for improvement.

Simply switching to warm-season varieties would reduce water needs by 20%, Baird said. However, these species go dormant in the winter, and even during their active months they never reach the deep green hues of their cool-season cousins.

"We could go a long ways in terms of our drought if more people used those grasses," he said. "But the color issue is the major limiting factor."

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