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Greenhouse Gas Emissions Under Different Drainage and Flooding Regimes of Cultivated Peatlands
Author(s) -
Hu Jing,
VanZomeren Christine M.,
Inglett Kanika S.,
Wright Alan L.,
Clark Mark W.,
Reddy K. R.
Publication year - 2017
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1002/2017jg004010
Subject(s) - greenhouse gas , peat , nitrous oxide , carbon dioxide , drainage , methane , environmental science , flooding (psychology) , global warming , global warming potential , hydrology (agriculture) , environmental engineering , environmental chemistry , zoology , agronomy , climate change , chemistry , ecology , geology , psychology , geotechnical engineering , organic chemistry , psychotherapist , biology
Globally, approximately 10–20% of peatlands have been drained for agricultural purposes. A strategy to protect peatlands and mitigate carbon dioxide (CO 2 ) emissions, while continuing agricultural production, is the use of intermittent flooding and drainage. A potential drawback of this strategy could be increases in methane (CH 4 ) and nitrous oxide (N 2 O) emissions. The objective of this study was to compare greenhouse gas (GHG) emissions from peatlands under various flooding–drainage cycles. A laboratory study was performed using intact soil cores subjected to different durations of flooding and drainage for 6 months. Average daily emissions of CO 2 and N 2 O were significantly higher ( P < 0.001) under drained (667 ± 37 mg CO 2 –C m −2 d −1 and 135 ± 19 μg N 2 O–N m −2 d −1 ) than flooded conditions (86 ± 6 mg CO 2 –C m −2 d −1 and 48 ± 2 μg N 2 O–N m −2 d −1 ). Methane emissions were not influenced by drained/flooded conditions, with an average rate of 116 ± 11 μg CH 4 –C m −2 d −1 . Peaks of CH 4 and N 2 O emissions were observed after flooding events and lasted less than 24 h. The peak emissions were approximately 8 and 19 times higher than the mean CH 4 and N 2 O emissions, respectively. Carbon dioxide was the dominant component of GHGs, irrespective of hydrologic regime, accounting for more than 92% of overall global warming potential. Global warming potential was inversely proportional to the flooding period, indicating that prolonging the flooding period of peatlands would help mitigate soil oxidation and GHG emissions and enhance sustainability of these agricultural peatlands.