Which gas is primarily produced by soil and manure management?

• A. Methane
• B. Ozone
• C. Nitrous Oxide
• D. Water Vapor

Answer: (C)

Nitrogen transformations in soils and manure systems are what this question is getting at. Microbes in these environments drive nitrification and denitrification, converting applied nitrogen from fertilizers or manure into different forms. Nitrous oxide is produced as a byproduct of these microbial steps, especially when conditions are wet and oxygen levels swing between aerobic and anaerobic. This makes nitrous oxide the gas most closely associated with soil and manure management. It’s a potent greenhouse gas with a high warming potential, and it also plays a role in ozone chemistry. Ozone and water vapor aren’t released directly in the same way from soil-management practices, and while methane can come from anaerobic manure processes, the link most emphasized for soil and manure management is nitrous oxide.