When we think of pollution that contributes to global warming, we think cars, and belching smokestacks. But farms? In the US, agriculture accounts for more than 8 percent of the country's greenhouse gas emissions.

But researchers have discovered that a simple technique called no-till farming could protect the soil and help fight climate change.

Healthy topsoil contains organic matter rich in carbon that provides nutrients to plants. Traditional plowing, or tilling, turns over that top layer of soil. This releases carbon-dioxide into the atmosphere. In no-till agriculture, farmers plant seeds without using a plow to turn the soil.

Researchers say no-till methods may reduce a farmer's annual crop yield by 5 to 10 percent, at least for the first few years. But the 2005 Farm Bill provides incentive payments for using no-till practices.

Farmers use no-till methods on 37 percent of the nation's cropland. This keeps an estimated 60 million metric tons of CO2 from being released each year.