HR: 08:45h
AN: B41D-03    [Abstracts]
TI: Factors Affecting Methane and Nitrous Oxide Emissions From Rice Fields
AU: * Khalil, M
EM: khalilm@pdx.edu
AF: Portland State University, Dept. Of Physics P.O. Box 751, Portland, OR 972070751 United States
AU: Shearer, M J
EM: mshearer@pdx.edu
AF: Portland State University, Dept. Of Physics P.O. Box 751, Portland, OR 972070751 United States
AU: Rasmussen, R A
EM: rei@ebs.ogi.edu
AF: OGI School of Science, OHSU, Dept. of Environmental & Bimolecular Systems 20,000 NW Walker Road, Beaverton, OR 97006 United States
AU: Xu, L
EM: xli@cma.gov
AF: Chinese Meteorological Administration, National Climate Center 46 Baishiqiao Road Western Suburb, Beijing, 10081 China
AB: Methane and nitrous oxide are important non-CO2 greenhouse gases. Agriculture in general, and growing rice in particular, are important anthropogenic sources of both. It is recognized that agricultural practices greatly affect methane emissions from rice fields, while less is known about nitrous oxide. The most significant factors are water management and fertilizer applications. Continuous inundation of the fields during the growing season and organic manure applications lead to high fluxes of methane while intermittent flooding and application of nitrogen based fertilizers lead to low emissions. The latter practice is becoming increasingly prevalent in China and possibly elsewhere. It leads to low methane emissions but higher nitrous oxide emissions. We have conducted detailed field experiments at three locations in China -Tu Zu and Jin Sa in Sichuan Province and Quin Yuan in Guangdong Province. In these experiments we have used established fields and taken our measurements under the prevailing agricultural practices of the local farmers. In the later studies we asked the farmers for some changes in practices to investigate and compare the emissions under the various prevailing water management and fertilization practices. We will discuss the effects of these two variables on the fluxes of methane and nitrous oxide from rice fields as determined in the field.
DE: 1615 Biogeochemical processes (4805)
DE: 0315 Biosphere/atmosphere interactions
DE: 0322 Constituent sources and sinks
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting