| 三江平原沼泽湿地N2O浓度与排放特征初步研究 |
| 摘要点击 3031 全文点击 2073 投稿时间：2001-12-26 修订日期：2002-06-18 |
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| 中文关键词 沼泽湿地 N2O 近地面浓度 排放特征 影响因素 |
| 英文关键词 wetland nitrous oxide concentration above the ground emission characteristics affect factors |
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| 中文摘要 |
| 2001年8月到9月在三江平原沼泽湿地进行N2O的原位静态箱观测.结果发现近地气层N2O平均浓度为281.7×10-9m3/m3,低于大气背景浓度,说明沼泽湿地可能是人类目前了解较少但很重要的N2O汇.选取积水状况和地表植被不同的毛果苔草沼泽、小叶章湿草甸(Ⅰ,Ⅱ)以及作为对照的小麦休耕地进行观测,发现4个地点的N2O排放日变化形式不完全相同,除小麦田全天持续排放N2O外,其余各点一天当中均出现排放与吸收交替出现的情况.温度是影响排放模式的主要因素.观测期内毛果苔草沼泽、小叶章湿草甸(Ⅰ,Ⅱ)和小麦休耕地N2O的平均排放强度分别为0.22μg/(m2·h),1.75μg/(m2·h),1.31μg/(m2·h)和4.86μg/(m2·h).氧化还原电位是决定沼泽湿地N2O排放特征的关键因子,地表积水情况和土壤水分状况则是影响N2O排放的另一重要因素. |
| 英文摘要 |
| N2O concentration and its flux were measured in Sanjiang Plain wetland,from August to September in 2001,by using in situ closed chamber technique. The results showed that the mean N2O concentration above the ground was 281.7×10-9 m3/m3,lower than the atmospheric N2O background, indicating the wetland maybe one of the important N2O sinks which scientists hadn't pay much attention to in the past. Four observation sites: Cares lasiocarpa,Alamagrostis angustifolia (Ⅰ,Ⅱ)and wheat land(had been harvested and in fallow) were chosen according to water content and plant. The daily N2O emission models at four sites were different from each other, except site of wheat land emitted N2O persistently all day, the other sites emitted and absorbed alternately in one day. Temperature was the crucial factor for the diurnal variation. The mean N2O flux at four sites from August to September was 0.22μg/(m2·h),1.75μg/(m2·h),1.31μg/(m2·h),4.86μg/(m2·h), respectively. Eh was the key factor for N2O emission characteristic in Sanjiang Plain wetland, and water content was another important factor. |
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