|Title||Soil air carbon dioxide and nitrous oxide concentrations in profiles under tallgrass prairie and cultivation|
|Publication Type||Journal Article|
|Year of Publication||1999|
|Authors||Sotomayor, D, Rice, CW|
|Journal||Journal of Environmental Quality|
Assessing the dynamics of gaseous production in soils is of interest because they are important sources and sinks of greenhouse gases. Changes in soil air carbon dioxide (CO2) and nitrous oxide (N2O) concentrations were studied in a Reading silt loam (fine-silty, mixed, mesic Typic Argiudolls) under prairie and cultivation. Concentrations were measured in situ over a 17-mo period to a depth of 3 m. Multilevel samplers permitted collection of gases with subsequent measurement by gas chromatography in the laboratory. Soil air N2O concentrations were near atmospheric levels for a majority of the study period in the prairie site (0.184–2.25 µL L−1) but were significantly higher in the cultivated site (0.257–7.56 µL L−1). Annual mean N2O concentrations were 0.403 and 1.09 µL L−1 in the prairie and cultivated sites, respectively. Soil air CO2 annual mean concentrations were 1.56 × 104 and 1.10 × 104 µL L−1 and ranged from 0.096 × 104 to 6.45 × 104 µL L−1 and 0.087 × 104 to 3.59 × 104 µL L−1 in the prairie and cultivated sites, respectively. Concentrations generally increased with depth, with maximum soil air N2O and CO2 concentrations at 1.0 m in the prairie site and 0.5 m in the cultivated site. Nitrous oxide in the cultivated site and CO2 at both sites did not change markedly over winter months, but CO2 and N2O concentrations reached maximums during the summer months and decreased as the year progressed. Although soil air concentrations peaked and decreased faster at shallower depths, deeper depths exhibited relative maximum concentrations for longer time periods.