Clark Williams-Derry points us to Washington State University's Climate Friendly Farming program.

About 10% of the carbon emitted in the US comes from agriculture, so reducing that is clearly a good, but it's on the other side of the equation, sucking carbon out of the air (carbon sequestration, as it's called) where the real gains can be made:

"Estimates of the potential for agricultural conservation practices to enhance soil carbon storage range from 154-368 million metric tons (MmtCE), which compare to the 345 MmtCE of reduction proposed for the U.S. under the Kyoto Protocol."

I don't know enough about farming to really judge the particulars here, but there's a lot of cool-sounding stuff here, like "improved anaerobic digesters for treating dairy waste" and "reduced-till non-monoculture crop rotation."