Sponsor
Major support for this work was supported by grants from the U.S. Department of Energy, Office of Science (BER), Grant Nos. DE-FG03-01ER63262 and DE-FG02-04ER63913. Additional support was provided by the resources of Andarz Co.
Published In
International Congress Series
Document Type
Post-Print
Publication Date
7-1-2006
Subjects
Greenhouse gases -- Research, Greenhouse gases -- China, Rice -- Research, Nitrous oxide
Abstract
Methane emissions from rice fields are controlled by several key factors. The most important are the application of organic soil amendments and water management: whether the fields are flooded intermittently or continuously. The total annual emissions from any country or the world are thus affected by the area of rice harvested, and a composite emission factor that takes into account how the various agricultural practices are distributed in terms of fertilizer use and water management, as well as other less important variables. Over decades the area of rice harvested changes but so does the composite emission factor. The product therefore, may change substantially over decadal time scales. We will argue that for China at least, there are downward trends of both area and emission factor leading to a substantial reduction of annual emissions over the last two decades from some 30 Tg/yr to perhaps less than 10 Tg/yr. The changes that cause these reductions would increase nitrous oxide emissions from rice fields as organic fertilizers are replaced with nitrogen based fertilizers. Similar changes are likely to be occurring world-wide. These trends of emissions are probably represented in the observed slowdown of methane trend in the atmosphere and the continuing steady increase of nitrous oxide.
DOI
10.1016/j.ics.2006.03.003
Persistent Identifier
http://archives.pdx.edu/ds/psu/7593
Citation Details
Khalil, M. A. and Shearer, Martha J., "Decreasing emissions of methane from rice agriculture" (2006). Environmental Science and Management Faculty Publications and Presentations. Paper 12. http://archives.pdx.edu/ds/psu/7593
Description
NOTICE: this is the author's version of a work that was accepted for publication in International Congress Series. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in International Congress Series, Volume 1293, July 2006, pages 33-41.
Article is available online at: https://doi.org/10.1016/j.ics.2006.03.003