372-8 Effect of Soil Moisture and Temperature on the Contribution of N2O Sources and Ammonia Oxidizer Growth in a Cropping Soil.
See more from this Division: SSSA Division: Soil Biology & Biochemistry
See more from this Session: Nitrification: New Players and Environmental Drivers: I
Wednesday, November 18, 2015: 2:10 PM
Minneapolis Convention Center, 103 BC
Abstract:
The continuous increase of the greenhouse gas nitrous oxide (N2O) in the atmosphere due to increasing anthropogenic nitrogen input in agriculture has become a global concern. In recent years, identification of the microbial sources responsible for soil N2O production has substantially advanced with the development of isotope enrichment and inhibition technologies and the discoveries of specific functional genes. However, little information is available to effectively quantify the N2O sources. Therefore it is necessary to improve the understanding of N2O formation and quantify the contribution of different pathways. To investigate this a 15N-tracing incubation experiment was conducted under controlled laboratory conditions (25°C, 35°C and 50%, 70% and 85% water filled pore space (WFPS)). Nitrification was found to be the main contributor of N2O production, having the greatest effect at the WFPS conditions of 50% and 70% WFPS. Nitrification contributed to 87%, 80% and 53% of total N2O production at 50%, 70% and 85%WFPS respectively at 25°C and to 86%, 74% and 33% of total N2O production at 50%, 70% and 85%WFPS respectively at 35°C. The proportion of nitrified N as N2O increased with increasing temperature and moisture, except at 85%WFPS. Ammonia oxidizing archaea (AOA) were the dominant ammonia oxidizers, but the ammonia oxidizing bacteria (AOB) population was significantly related to N2O emitted from nitrification (p < 0.05). Soil moisture had a more significant (p < 0.05) influence on AOA and AOB abundance compared to soil temperature. Increasing moisture content significantly (p < 0.05) decreased AOA and AOB abundance. These findings can be used to develop better models for simulating N2O from nitrification to inform soil management practices for improved N use efficiency.
See more from this Division: SSSA Division: Soil Biology & Biochemistry
See more from this Session: Nitrification: New Players and Environmental Drivers: I
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