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Effects of elevated CO 2 and N fertilization on CH 4 emissions from paddy rice fields
Author(s) -
Xu Zhongjun,
Zheng Xunhua,
Wang Yuesi,
Han Shenghui,
Huang Yao,
Zhu Jianguo,
ButterbachBahl Klaus
Publication year - 2004
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2004gb002233
Subject(s) - methane , paddy field , human fertilization , carbon dioxide , nitrogen , urea , chemistry , environmental chemistry , zoology , agronomy , biology , organic chemistry
The authors employed free‐air carbon dioxide enrichment facilities for investigating the effects of elevating the present atmospheric CO 2 by 200 μmol mol −1 and increasing the application rate of urea‐based fertilizers from 150 to 250 kg N ha −1 on CH 4 emissions from paddy rice fields in southeastern China. The elevated CO 2 significantly stimulated methane emission, which was mainly due to the stimulation in rice growth. Intensifying N fertilization mitigated the CH 4 emission under the ambient CO 2 but stimulated the CH 4 emission under the elevated CO 2 . This suggests that N fertilization has a potential to stimulate both CH 4 production and CH 4 oxidation. Thus the net effect of N fertilization on CH 4 emission from paddy rice fields most likely depends upon the counterbalance between the nitrogen‐induced increases in CH 4 production and CH 4 oxidation, as a N excess may result in the inhibition of methane emission, whereas a N limitation may result in the stimulation of methane emission.