Factors Influencing Methane (CH4) and Nitrous oxide (N2O) Emissions from Soils: A Review

Abstract

Methane (CH4 ) and nitrous oxide (N2O) are the two most important non-carbon dioxide (CO2 ) greenhouse gases (GHGs) that play a critical role in shaping the global climate. Their concentrations in the atmosphere have been significantly increased by human activities. CH4 has contributed to an estimated 18–20% of post-industrial anthropogenic global warming and is 25 times more effective in absorbing radiation that atmospheric CO2 . Its production and consumption in soils is affected by numerous factors including water table depth. Nitrous oxide is one of the key ozone (O3 ) depleting gases, constituting 7% of the anthropogenic greenhouse effect. On a molecular basis, N2O has 298 and 16 times higher global warming potential than that of CO2 and CH4 respectively over a 100-year period. Nitrous oxide is produced in soils by denitrification and nitrification processes. It is affected by many physical and biochemical factors such aeration/moisture status of the soil.