Determination of Soil-Related Trace Gas Fluxes during the Cultivation of Renewable Raw Materials

Abstract

The emission of climate- and environmentally relevant trace gases af- fects the environmental balance of renewable raw materials. Depending on the intensity and the kind of nitrogen fertilizing, additional nitrous oxide or ammonia is emitted, and methane degradation in the soil is in- fluenced. These trace gas fluxes are measured using the flux chamber method in connection with gas chromatography (GC) and Fourier- transform infrared spectroscopy (FT-IR). The GC technology provides the advantage of higher accuracy for some selected trace gases. The FT- IR measurements show that the release of ammonia caused by fertilizing with calcium ammonium nitrate is below the detection limit. The nitrous oxide emission factor measured at a loamy-sandy location is based on GC results. The average quantity of all fertilizer-induced N2 O-N emis- sions only amounts to approximately 0.2 % of the annual quantity of N- fertilizer applied. In addition, the GC measurements show that the de- gradation of atmospheric methane in the soil depends on the soil tem- perature. The mean annual value of methane degradation at the exam- ined location amounts to 0.7 kg CH4 ha-1 a -1.