| View Larger Image | The effects of ammonium sulfate application on methane emission and soil carbon content of a paddy field in Japan [An article from: Agriculture, Ecosystems and Environment] | Digitalby K. Minamikawa (Author), N. Sakai (Author), H. Hayashi (Author)
| List Price: | $10.95 | | | Available: | Available for download now |
| | Binding: | Digital | | Publisher: | Elsevier | | Publication Date: | May 30, 2005 |
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Product Description
This digital document is a journal article from Agriculture, Ecosystems and Environment, published by Elsevier in 2005. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.Description: Decreases in methane (CH"4) emission from paddy fields are important for mitigating global warming. Some substrates such as soil carbon are used by methanogens for CH"4 production. Thus, changes in CH"4 emission may be accompanied by changes in soil carbon content. This study was carried out at an experimental paddy field in Agricultural and Forestry Research Center, University of Tsukuba, Japan. The experimental variables were rates of ammonium sulfate application (AS; 0, 45, 90, and 135kgNha^-^1) and levels of rice (Oryza sativa L., cultivar: Koshihikari) plant density (PD; 18.5 and 30.3hillm^-^2). During the rice growing period, we measured CH"4 emission by a closed-chamber method, and soil carbon content. Then, we considered the effects of the variables on CH"4 emission and soil carbon content, and analyzed the quantitative relationship between them. There were no effects of PD level on CH"4 emission and soil carbon content. This was likely due to the compensatory effect of rice plants. The CH"4 emission decreased with increases in AS application rate, caused by competition for substrates between sulfate-reducing bacteria and methanogens. Decreases in soil redox potential (E"h) were delayed with increases in AS application rate. This process was another cause for the decreased CH"4 emission at higher rates of AS application, but the reason for the higher soil E"h is not clear. Soil carbon content decreased with increases in AS application rate. Thus, there was a positive linear correlation between CH"4 emission and soil carbon content (R^2=0.977). Consequently, although AS application was effective to decrease CH"4 emission, it simultaneously stimulated soil carbon decomposition. Carbon is stored in the soil in huge quantities, and is partly decomposed to carbon dioxide, also a greenhouse gas. Thus, it is necessary to consider not only CH"4 emission but also soil carbon storage for mitigating global warming. |
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