Monday, November 13, 2006
89-3
The Influence of Moisture Content and Nitrogen Supply on Microbial Sources of Nitrous Oxide.
Nicole Wrage1, Dorien M. Kool2, Oene Oenema3, Elizabeth M. Baggs4, and Jan W. Van Groenigen2. (1) Dept. of Crop Sciences, University of Gottingen, Von Sieboldstrasse 8, Gottingen, Germany, (2) Alterra, Soil Sciences Center, PoOBox 47, Wageningen, 6700AA, Netherlands, (3) "Alterra, Soil Sciences Center", Po Box 47, Po Box 47, Wageningen, 6700AA, NETHERLANDS, (4) School of Biological Sciences, University of Aberdeen, Cruickshand Building, St. Machar Drive, Aberdeen, United Kingdom
We investigated the effect of water-filled pore space (WFPS) and nitrogen source on N2O production from nitrification, nitrifier denitrification and denitrification. To differentiate between N2O sources, the dual-isotope method1 was used. This method involves the use of double- and single-15N-labelled NH4NO3 and of 18O-labelled water (H2O). A range of WFPSs from 10 to 80% was tested, with either NH4+ or NO3- as the main N source. The N source had not much impact on different N2O production pathways, except for nitrification-coupled denitrification, which was larger with added NH4+ than with NO3-. WFPS influenced both the total amount of N2O production and the relative contribution of the different pathways. Preliminary results indicate the importance of nitrifier denitrification for N2O production in this soil, both at intermediate and high WFPS.