FARGO - North Dakota farmers have the chance to get paid for conservation practices that keep carbon dioxide in the ground.

The North Dakota Farmers Union on Wednesday unveiled a program that would pool carbon credits for sale at a private agency that trades greenhouse gases and pollutants, much like other exchanges trade commodities.

Supporters of the plan say it's a way to reward farmers who want to help cut down on global warming.

"We think this is one of the most exciting projects to come about in a long time," said Keith Trego, director of the North Dakota Natural Resources Trust. "We hope that income will grow over time as interest in this issue continues to grow around the world."

The Chicago Climate Exchange is selling carbon credits at about $1.50 per acre for no-till land and $2.50 per acre for land seeded to grass after Jan. 1, 1999. The actual payment will depend on market prices.

Normally, producers on a 1,300-acre farm, the average size in North Dakota, could expect about $2,000 a year, Carlson said. "We'll find out" if that's attractive enough for producers, he said.

"It's certainly better than no incentive," Carlson said.

No-till farming uses a machine that can place seed, fertilizer and sometimes chemicals into the ground without tilling the soil first. Along with storing carbon in the soil, it saves fuel and reduces soil erosion, Carlson said.

"It's been around long enough that people have seen their neighbors successfully no-till and they know it can work," he said. "In the eastern part of the state, where the soil is heavier, there isn't as much no-till, but it certainly has been used a lot in the western part."

Some form of conservation tillage is being used on about 8 million of the 21 million acres of cropland in the state, said J.R. Flores, spokesman for the North Dakota Natural Resources Conservation Service in Bismarck. Those producers are immediately eligible for carbon credits.

"I'm guessing that for producers who are currently doing no-till and are experienced at it, this is going to be kind of a no-brainer for them," Carlson said. "But we'll see. Farmers are kind of cautious. They want to see how things work for their neighbors sometimes before they plunge into it themselves."

North Dakota Farmers Union is looking to expand the program into Minnesota, Wisconsin, South Dakota and Montana, Carlson said. The Iowa Farm Bureau runs a similar program for farmers in Iowa, Nebraska and Kansas.

The Chicago Climate Exchange opened in 2003 with 14 members, mostly major industrial companies, said Nathan Clark, an economist for the company. The group now has about 200 members, including universities, cities and states.

Polluters can buy carbon credits to help balance out their emissions.

"I know many people have talked about this happening for years and years, and finally the theory has become reality," Clark said.

There's no fee to enroll in the program, but the Farmers Union will receive 10 percent commission. Producers can enroll online at www.ndfu.org.