Optimizing grain yields reduces CH4 emissions from rice paddy fields
- H. A. C. Denier van der Gon†,‡,
- M. J. Kropff§,
- N. van Breemen†,¶,
- R. Wassmann∥,
- R. S. Lantin**,
- E. Aduna**,
- T. M. Corton††, and
- H. H. van Laar§
- †Laboratory of Soil Science and Geology, Wageningen University, P.O. Box 37, 6700 AA Wageningen, The Netherlands;§ Laboratory of Crop and Weed Ecology, Wageningen University, P.O. Box 430, 6700 AK Wageningen, The Netherlands;∥ Fraunhofer-Institut für Atmosphärische Umweltforschung, Kreuzeckbahnstrasse 19, D-82467 Garmisch-Partenkirchen, Germany; **Soil and Water Sciences Division, International Rice Research Institute, P.O. Box 3127, MCPO 1271, Makati City, Philippines; and ††Agronomy, Soils, and Plant Physiology Division, Philippine Rice Research Institute, Munoz, Nueva Ecija 3119, Philippines
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Edited by Ralph J. Cicerone, University of California, Irvine, CA, and approved July 22, 2002 (received for review May 8, 2002)
Abstract
Microbial production in anoxic wetland rice soils is a major source of atmospheric CH4, the most important non-CO2 greenhouse gas. Much higher CH4 emissions from well managed irrigated rice fields in the wet than in the dry season could not be explained by seasonal differences in temperature. We hypothesized that high CH4 emissions in the wet season are caused by low grain to biomass ratios. In a screenhouse experiment, removing spikelets to reduce the plants' capacity to store photosynthetically fixed C in grains increased CH4 emissions, presumably via extra C inputs to the soil. Unfavorable conditions for spikelet formation in the wet season may similarly explain high methane emissions. The observed relationship between reduced grain filling and CH4 emission provides opportunities to mitigate CH4 emissions by optimizing rice productivity.
Footnotes
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↵ ‡ Present address: TNO Institute of Environmental Sciences, Energy Research and Process Innovation, P.O. Box 342, 7300 AH Apeldoorn, The Netherlands.
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↵ ¶ To whom reprint requests should be addressed. E-mail: nico.vanbreemen{at}bodeco.beng.wau.nl.
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This paper was submitted directly (Track II) to the PNAS office.
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See commentary on page 11993.
- Abbreviations:
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HI, harvest index
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- Copyright © 2002, The National Academy of Sciences
