Soils may act either as a source of carbon by releasing carbon to the atmosphere or soils may act as a sink by depositing atmospheric carbon back into the soils. Land management is the critical factor that determines whether the net change in soil carbon is a gain or loss. Methane and nitrous oxide are also influenced by agricultural practices. Nitrous oxide is produced by bacteria breaking down nitrogen in the soil. Therefore, the levels of nitrogen fertilizers applied and when application takes place can affect the nitrous oxide levels in the atmosphere.
Methane emissions are due to livestock production.
Manure handling and management of grass-based animal production systems can help control the levels of methane. A study by Michigan State University shows that conventional tillage has a gross warming potential of 114 while no-till reduced this gross warming potential 88 percent to a value of 14. The 1997 Kyoto Protocol, is trying to get industrialized countries to decrease their greenhouse gas emissions by an average of 5 percent from 1990 levels for a five-year period from 2008 to 2012. Although this sounds like more regulations for farmers to deal with, it actually presents potential profit opportunities. Efforts have already begun to help give farmers and businesses credit for carbon storage.