Fertilized soils release more than 2 billion tons of greenhouse gases every year
"Soils with nitrogen fertilizers release nitrous oxide, a greenhouse gas that has about 300 times the warming capacity of carbon dioxide. Fertilized soils release more than 2 billion tons (in terms of carbon dioxide equivalent) of greenhouse gases every year."
Sara J. Scherr and Sajal Sthapit. "Farming and Land Use to Cool the Planet," State of the World 2009 2009, 35.