242-8 Assessment of Nitrous Oxide and Methane Emissions In Rice Based Cropping Systems.



Tuesday, October 18, 2011: 10:25 AM
Henry Gonzalez Convention Center, Room 207A, Concourse Level

John Duxbury, Center for a Sustainable Future, Cornell University, Ithaca, NY
Approaches to measuring N2O and CH4 emissions from rice based cropping systems are briefly discussed.  Accurate assessment of annual fluxes requires continuous monitoring.  For paddy rice, CH4 emissions occur with continuous flooding, i.e. under highly reduced conditions, and are increased substantially by organic material additions.  In contrast N2O, emissions occur under times of transition to and from flooding and during wet periods for any rotational upland crops.  Intermittent drainage of rice paddies to reduce CH4 emissions leads to conditions where N2O can be emitted thus creating a trade-off between the two greenhouse gases.  Volatilization of NH3 before canopy closure is also a common nitrogen loss mechanism in rice paddies.  Atmospheric NH3 reactions with acidic species promote smog formation, and its deposition on plant and land surfaces can contribute to off-site emissions of N2O. 
See more from this Division: S01 Soil Physics
See more from this Session: Symposium--Emission of Regulated and Greenhouse Gases: Measurement Technology, Monitoring and Policy: I