Profile Nitrous Oxide and Carbon Dioxide Concentrations in a Soil Subject to Freezing
- D. L. Burton and
- E. G. Beauchamp
Soil is an important source for the production of greenhouse gases such as CO2 and N2O. Significant temporal trends exist in the production and concentration of these gases in temperate climates where soils are subject to freezing. We examined the effect freeze-thaw cycles had on soil profile CO2 and N2O concentrations. A multilevel sampling probe was designed to allow sampling the atmosphere composition of soil profiles. Changes in CO2 and N2O gas concentrations in the profile of a loamy sand were studied during two winter periods. Fluxes of N2O were strongly influenced by the formation of a frozen layer that segregated the soil profile into two distinct regions. The surface region was characterized by brief, intense events, which contribute to highly variable CO2 and N2O concentrations near the surface. The subsurface region beneath the ice layer allowed N2O accumulation. The highest concentrations of N2O were observed in the subsurface region following ice-layer formation, indicating that N2O production is not restricted to surface horizons in this soil. Thawing of the frozen layer in the spring resulted in the release of N2O from the subsurface region. The formation of a frozen layer influenced subsurface CO2 accumulation through its influence on water percolation.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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