137-15 Effect of Oxygen Content on Pathway of Nitrous Oxide Production from Different Nitrogen Fertilizers.



Monday, October 17, 2011
Henry Gonzalez Convention Center, Hall C, Street Level

XIA ZHU, Univeristy of California davis, DAVIS, CA and William R. Horwath, LAWR, University of California-Davis, Davis, CA
When aiming to develop adequate mitigation strategies for emission of nitrous oxide (N2O) from soils, an accurate understanding of biochemical N2O production pathways in soil is advantageous.  Nitrification, nitrifier denitrification, denitrification are considered as the main pathways of N2O production, depending on soil conditions such as soil pH and oxygen (O2) content. Most nitrogen fertilizers supply ammonium to the soil-plant system, some of which give an acidic reaction while others can temporarily raise soil pH. The primary pathway of N2O production will therefore change based on the fertilizer type applied. At the same time, O2 content is also a very important factor determining N2O emission. However, there is still only limited understanding of how the mechanism of N2O production from different fertilizers changes as O2 becomes limiting. We used two agricultural soils to investigate the effect of urea, ammonium sulfate, monoammonium phosphate, and aqueous ammonia on the pathways of N2O production under an oxygen atmosphere of 21, 3, 0% O2. In both soils, N2O emission from urea was significantly higher than the other fertilizer types under 21 and 3% O2. Based on the relative amount of N2O produced among treatments, nitrifier denitrification is likely the main source of N2O from all fertilizer types under 3% O2.
See more from this Division: S06 Soil & Water Management & Conservation
See more from this Session: Agricultural Practices to Increase Nitrogen-Use Efficiency, Carbon Sequestration, and Greenhouse Gas Mitigation : II