by Julene Bair

"The magnificence of being." In 1877, that's what the early plainsman Richard I. Dodge reported feeling on the open grasslands.

Unfortunately, by the 1990s that ecosystem had become one of the world's most threatened. In Kansas, where I grew up, crops had replaced about 70 percent of the prairie. Some Midwestern states lost nearly 100 percent.

The federal government encouraged all that sod busting, first with the Homestead Act and then with farm subsidies, which made it more profitable to grow crops than to graze livestock. Denuding so much land of soil-binding grass has hurt our topsoil, water and wildlife.

Our sense of beauty, like our other impulses, probably evolved to help us survive. When we see clear streams, healthy forests or sweeping grasslands and find them beautiful, we should have enough sense not to destroy them.

It seems obvious, the kind of thing you don't need a study to prove. But we are a little too good at ignoring the obvious.

Now, with 97 percent of scientists surveyed by Harris Interactive agreeing that global warming is a reality, we fail to recognize the benefits of grasslands at our peril. The soil beneath a square meter of shortgrass prairie contains up to five miles of roots. All that biomass stores carbon. Soil converted from grass to crops loses 20 to 50 percent of its organic carbon. Where does it go? Primarily into the atmosphere, as carbon dioxide, a greenhouse gas.

Despite this, the government is subsidizing corn ethanol and mandating increases in biofuel use. In the Feb. 29 edition of Science, researchers estimate that corn-based ethanol production will nearly double greenhouse emissions over 30 years, because it will mean the conversion of grasslands and forests into cropland.

Largely to meet demand for ethanol, U.S. corn acreage increased by nearly 20 percent last year. Part of this came from pastureland and land formerly in the Conservation Reserve Program, which pays farmers to replant grass. Last September, when many CRP contracts came up for renewal, growers withdrew 2.5 million acres.

I have witnessed the result of America's biofuel policy on my family's western Kansas farm. After we sold it recently, the new owner planted corn where our pasture had been. The crop died in the summer heat, as corn without irrigation often does on the High Plains.

But who could blame him? Corn was selling for twice what it had in the past, and with government-subsidized crop insurance, he could afford the gamble.

The 2008 farm bill will finally limit subsidies on newly broken sod, but only for the first four years. And in many cases, crop prices alone will be enough incentive for farmers to plow up grass. Partly due to corn's displacement of wheat and soybeans, prices for those commodities also have soared.

The world's poor suffer most. Headlines announce food riots and starvation, while we Americans pump ethanol down the gullets of our infamous SUVs. The corn in one fill-up, says Lester Brown, president of the Earth Policy Institute, could feed a human for a year.

But even if we fed the grain to people instead of cars, CRP land and most remaining virgin prairie are not good candidates for crops. In the mostly flat farm country I come from, land escaped the plow or went into CRP usually because it was too hilly. Highly erodible and unproductive, those acres are best suited for grazing.

In the words of the U.N. Environment Program, we need to "feed the world without starving the planet." If we choose instead to continue planting crops on poor rangeland, the plow-up will not only diminish what's left of the land's magnificence. More soil will erode, more water will be wasted or ruined, more wildlife habitat will be destroyed, and our climate will worsen.

The U.N. Intergovernmental Panel on Climate Change warns that higher temperatures resulting from atmospheric carbon dioxide will cause "increasing drought in midlatitudes and semiarid low latitudes." The world's grasslands, that is. Today's croplands. The Great Plains.

Rain doesn't follow the plow, as Plains settlement boosters once promised. But drought might.

Julene Bair, of Longmont, Colo., is the author of "One Degree West" and "The Whole Song." Her Web site is www.julenebair.com. She wrote this comment for the Land Institute's Prairie Writers Circle, Salina, Kan.