Details

Autor(en) / Beteiligte

• Valente, Ralph J.
• Thornton, Frank C.

Titel

Emissions of NO from soil at a rural site in central Tennessee

Ist Teil von

• Journal of Geophysical Research (0148-0227), 1993-09, Vol.98 (D9), p.16745-16753

Ort / Verlag

Washington, DC: Blackwell Publishing Ltd

Erscheinungsjahr

1993

Beschreibungen/Notizen

• Field measurements of soil emissions of NO from a Mountview silt loam soil with three land uses (forest, fertilized pasture, and fertilized corn) were made on a commercial farm during a summer and autumn sampling period. A new automated closed‐chamber sampling system was developed to allow simultaneous measurements on five chambers per 100 m2 plot. Individual chambers with hinged tops, covering 0.3 m2 of soil area were pneumatically operated via data logger control to sample soil NO flux every third hour. Spatial variability in emission rates was high. For each land use type the range from the lowest to the highest emitting chamber was approximately threefold. Land use type significantly affected soil NO emissions. The fertilized pasture had the highest mean emission rate (44.1 ng N m−2 s−1), followed by the fertilized corn (27.0 ng N m−2 s−1), and the forest (8.4 ng N m−2 s−1). NO emission rates and soil nitrate levels at the forest plot were considerably higher than at other forest sites in the region, possibly due to runoff from an adjacent fertilized hayfield. The results of this study, when extrapolated to a regional estimate, suggest that emissions of NO from soils could play a significant role in summertime tropospheric ozone photochemistry in the southeastern United States.