| 干湿交替条件下不同晶型铁氧化物对水稻土甲烷排放的影响 |
| 摘要点击 2585 全文点击 1423 投稿时间：2013-07-14 修订日期：2013-08-19 |
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| 中文关键词 水稻土 干湿交替 铁氧化物 甲烷排放 产甲烷潜力 |
| 英文关键词 paddy soil drying/wetting cycle iron oxides methane emission methane production potential |
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| 中文摘要 |
| 以典型华南水稻土为研究对象，通过室内恒温培养试验，分析了不同水分条件下[干湿交替（DW）和持续淹水（CF）]不同晶型铁氧化物[水铁矿（SF）和赤铁矿（SH）]对水稻土 CH4平均排放速率及产 CH4潜力的影响. 结果表明，与 CF相比，DW处理的CH4平均排放速率平均减少了 61%以上；与没有添加铁氧化物的处理相比，铁氧化物抑制了 53%的 CH4排放. DW与铁氧化物的耦合抑制了 65%~94%的产 CH4平均排放速率及 57%~93%的产 CH4潜力，抑制效果明显高于DW或铁氧化物的单独作用. 其中DW耦合晶型较弱的水铁矿（SF-DW）所产生的抑制效应（94%）明显高于DW耦合晶型较好的赤铁矿（SH-DW，65%）. 统计分析结果表明 Fe（Ⅲ）浓度与水稻土CH4排放速率存在显著负相关性（R2=-0.98，P<0.01）. 且实验结果表明，DW可以加速Fe（Ⅲ）的循环再生，而晶型较弱的SF易还原性使其 Fe（Ⅲ）的循环再生更易受到DW的影响. 上述结果说明，DW可以促进铁氧化物对水稻土 CH4排放 及产CH4潜力的抑制效应，且干湿交替与晶型较弱的水铁矿的耦合效应比干湿交替与晶型较高的赤铁矿的耦合效应更为显著. |
| 英文摘要 |
| This study investigated the effects of iron oxides with different crystallinities, ferrihydrite (SF) and hematite (SH), on the methane emission in paddy soil of South China under different water conditions, alternative drying/wetting cycles (DW) and continuous flooding (CF). The rates of methane emission, methane production potential and concentrations of Fe(Ⅱ) and Fe(Ⅲ) were determined. Results showed that compared with CF, the average methane emission rate was greatly inhibited by DW over 61%, and the addition of iron oxides reduced methane emission rates by 53%. Under the circumstance of DW and iron oxides addition, the combined inhibition effect on the average methane emission(65%-94%) and methane production potential (57%-93%) was significantly higher than the single effect caused by DW or iron oxides. Interestingly, DW coupling poorly crystalline ferrihydrite (SF-DW, 94%) posed a more significantly inhibitory effect on the methane emission than coupling crystalline hematite (SH-DW, 65%). Statistical analysis showed that there was a significantly negative correlation between the Fe(Ⅲ)concentrations and the methane emission rates (R2=-0.98,P<0.01). Experimental results showed that DW facilitated the cyclic regeneration of Fe(Ⅲ), and the Fe(Ⅲ)/Fe(Ⅱ) cycle in poorly crystalline ferrihydrite was more susceptible to DW than hematite. This study suggested that alternative drying/wetting cycles can remarkably enhance the inhibitory effect of iron oxides on methane emission from paddy soil, and the coupled suppression effect of DW and poorly crystalline ferrihydrite is more obvious than the coupled effect of DW and crystalline hematite. |
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