Gauci, V.; Dise, N. B. and Howell, G.
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Large individual applications of SO42-(102-103 kg SO42--S/ha) are known to suppress methane emissions from rice paddies by up to ~70%. The application of large quantities of SO42- amendments to rice paddies has therefore been proposed as a greenhouse gas mitigation strategy. In a similar system, natural peatlands, research has established that very low rates of SO42- deposition (~25 kg SO42- -S/ha/yr as small weekly pulses), similar to those of regions experiencing acid rain pollution, suppress methane emissions by as much as 30-40%. It is thought that this is due to stimulation of sulfate-reducing microbial populations that out-compete methane producers for substrates. Given that acid rain S pollution is forecast to increase in Asia, the major rice growing region, we sought to establish the potential for acid rain to suppress CH4 emission from rice agro-ecosystems by experimentally simulating acid rain inputs of S deposition to rice mesocosms in the laboratory. We used soils from Portuguese rice growing regions as they experience low ambient S deposition, and investigated the effect of simulated sulfate deposition (small regular pulses) on CH4 emissions, pore- water concentrations of CH4 and alternate electron acceptors. We also applied an annual dose of S deposition as a single pulse of sulfate to one set of replicate rice mesocosms. After a lag time of 7 weeks, CH4 emission from the mesocosms subjected to the small weekly applications of ‘acid rain' sulfate as Na2SO4 at a rate of 100 kg SO42- -S/ha/yr (amounting to a total deposition of ~20 kg SO42- -S/ha throughout the 10 week experiment) were reduced below the control by an average of 22%, and as much as 35% on a single date. CH4 emissions from the ‘single pulse' experiment were significantly suppressed by the applied sulfate as were pore-water CH4 concentrations.
|Item Type:||Conference Item|
|Copyright Holders:||2006 The Authors|
|Extra Information:||Go to bottom of URL page to session B31D-07
Gauci V., Dise NB., Howell G., (2006), Suppression of rice methane production and emission by low dose sulfate application, Eos Trans. AGU, 87(52), Fall Meet. Suppl., Abstract B31D-07
|Academic Unit/Department:||Science > Environment, Earth and Ecosystems
|Interdisciplinary Research Centre:||OpenSpace Research Centre (OSRC)
Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
|Depositing User:||Vincent Gauci|
|Date Deposited:||23 Feb 2012 15:26|
|Last Modified:||23 Feb 2012 15:26|
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