One of the world's worst pollution problems is carbon dioxide, belched from factory smokestacks and other industrial emissions. It's one of the so-called greenhouse gases that most scientists now say are causing un-natural changes in the earth's climate. But there's a way to prevent the build-up of carbon dioxide before it contributes to global warming. Part of that solution is found on the American Prairie.

The cornhusks are withering away to a pale gray in the same field where farmer Steve Tuttle checks grass-like sprouts of winter wheat poking through the soil. "This wheat really looks good. It was planted the 20th of September, if I remember right," he says.

The first-generation farmer will harvest his crop this summer. In the meantime, the decaying cornhusks that are crunching underfoot will replenish the nutrients in the soil, taking the place of some of the fertilizer used in traditional farming. Mr. Tuttle doesn't till the land when he plants his crops. As he drives his green tractor across his fields, he tows a wide planter that barely pierces the soil to deposit seeds. It's called no-till farming, Mr. Tuttle says it saves him time and fuel costs, and it's better for the environment.

"Any time you till the soil, you release carbon into the atmosphere, by the breaking down of the organic matter in the soil," he explains. "So by leaving the soil surface undisturbed, and planting into the prior crop's residue, that helps capture and hold that carbon that's in the plant residue and it adds to the carbon in the soil so we can bank that carbon basically and store that."

Carbon is pulled from the air and stored in the ground through photosynthesis. Green plants absorb carbon dioxide from the air, convert it into energy for growth and release oxygen back into the atmosphere. The carbon makes its way into the soil through the plants' root system, where it will stay until the ground is disturbed by farming or development. Holding carbon in the soil is called sequestration and scientists say it could be an important part of a pollution-fighting strategy. "If you do some of these soil management practices, like re-planting of grasses, no-till agriculture, different rotation systems with farming, they all improve the carbon storage capacity of that soil," says Chuck Rice of Kansas State University, who leads a group researching how agriculture might be used to fight global warming. "There's been some work that shows that somewhere around 20 percent of U.S. emissions can be sequestered in soil."

A $15 million federal grant is paying for more research into fighting pollution with responsible agricultural practices. But carbon sequestration offers more than an environmental benefit, it's presented farmers with a financial opportunity. Many are already looking to a developing market that trades carbon pollution in the air for carbon in the soil.

The Chicago Climate Exchange is about to become a broker between companies that release greenhouse gases from their factories and others that offset those emissions by farming or managing forests. In a more informal arrangement, a power plant in America's Pacific Northwest pays local farmers to apply no-till farming techniques to their land.

Kansas Senator Sam Brownback says he sees the market expanding as financial opportunities arise. "We want to reduce that growth of CO-2 and one of the key ways it seems to a number of us as a way to do that is to create a carbon market," he points out. "And in this market you'd have some people securing carbon in the soil and other people would be releasing carbon. Farmers could economically and competitively bid for carbon sequestration, still be able to operate their land but use it as a second income source and a clear environmental benefit."

As he surveys his wheatfield on this cold day, farmer Steve Tuttle says when the market opens up in Kansas, he'll sign up. "We're looking at every income stream we can get. Our costs are really squeezed down tight," he explains. "So, if we can get another revenue stream brought in to the farm that's just gonna be that much better for us to help our operation survive."

The relatively new practice of no-till farming is slow to replace methods used for generations. And scientists and lawmakers say the key now is to convince more farmers to adopt the technique.

Its supporters, like Steve Tuttle, hope the prospect of earning more money - as much as $7 to $8 per hectare - will provide a financial incentive for farmers to change from old ways to new in the years to come.