Scientists have long known that there are ebbs and flows in the exchange of CO2 between plants and the air.
In the summer, there's a net uptake of carbon dioxide; in the winter stalks and roots break down and send CO2 in the air.
Recently, scientists have found that farming accounts for a 25 percent increase in carbon activity, much of it from the the United State's biggest crop - corn.
But as, Harvest Public Media reporter Grant Gerlock explains, the jump in carbon activity doesn't necessarily mean that farming is accelerating climate change.
This segment aired on February 5, 2015.