Soils, a sink for N₂O? A review

• Published in: Global change biology Vol. 13; no. 1; pp. 1 - 17
• Main Authors: CHAPUIS-LARDY, LYDIE, WRAGE, NICOLE, METAY, AURÉLIE, CHOTTE, JEAN-LUC, BERNOUX, MARTIAL
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.01.2007; Blackwell Publishing Ltd; Wiley
• Subjects: denitrification; Environmental Sciences; gas diffusion; Global Changes; global N2O budget; global N₂O budget; greenhouse gas; greenhouse gases; N2O consumption; negative flux; nitrification; nitrous oxide; N₂O consumption; GLOBAL N2O BUDGET; NEGATIVE FLUX; N2O CONSUMPTION; NITRIFICATION; DENITRIFICATION; GREENHOUSE GAS; GAS DIFFUSION; NITROUS OXIDE
• ISSN: 1354-1013; 1365-2486
• DOI: 10.1111/j.1365-2486.2006.01280.x

Soils are the main sources of the greenhouse gas nitrous oxide (N₂O). The N₂O emission at the soil surface is the result of production and consumption processes. So far, research has concentrated on net N₂O production. However, in the literature, there are numerous reports of net negative fluxes of N₂O, (i.e. fluxes from the atmosphere to the soil). Such fluxes are frequent and substantial and cannot simply be dismissed as experimental noise. Net N₂O consumption has been measured under various conditions from the tropics to temperate areas, in natural and agricultural systems. Low mineral N and large moisture contents have sometimes been found to favour N₂O consumption. This fits in with denitrification as the responsible process, reducing N₂O to N₂. However, it has also been reported that nitrifiers consume N₂O in nitrifier denitrification. A contribution of various processes could explain the wide range of conditions found to allow N₂O consumption, ranging from low to high temperatures, wet to dry soils, and fertilized to unfertilized plots. Generally, conditions interfering with N₂O diffusion in the soil seem to enhance N₂O consumption. However, the factors regulating N₂O consumption are not yet well understood and merit further study. Frequent literature reports of net N₂O consumption suggest that a soil sink could help account for the current imbalance in estimated global budgets of N₂O. Therefore, a systematic investigation into N₂O consumption is necessary. This should concentrate on the organisms, reactions, and environmental factors involved.