Carbon dioxide concentration in soil. Effects on nitrification,denitrification and associated nitrous oxide production

Experiments were conducted to study the effects of a range of CO₂ concentrations (ambient to 100%) on nitrification, denitrification and associated nitrous oxide (N₂O) production in a silt loam soil. It was found that increase in CO₂ concentration from 0.3 to 100% CO₂ increasingly retarded the rate of nitrification. No nitrification occurred at 100% CO₂. Nitrous oxide production associated with nitrification increased as CO₂ increased from 0.3 to 2.6% and tended to be greater as CO₂ concentration increased to 73%. At 100% CO₂, no N₂O was produced during 7 days at 25°C.Carbon dioxide did not affect N₂O production or reduction in a saturated NO₃^?amended soil or the rate of N₂O reduction in anaerobic environments.