| 黄土高原坝系流域干湿季交替下氮输出特征及其源解析:以羊圈沟为例 |
| 摘要点击 2244 全文点击 837 投稿时间：2016-04-12 修订日期：2016-08-01 |
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| 中文关键词 黄土高原 坝系流域 氮湿沉降 输出负荷 同位素 |
| 英文关键词 Loess Plateau dam watershed nitrogen wet deposition output load isotope |
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| 中文摘要 |
| 本研究通过对干湿季氮湿沉降过程、降雨过程及基流过程进行动态监测，分析干湿季交替下降雨及基流过程的各形态氮浓度变化，探讨黄土高原坝系流域氮湿沉降对流域氮输出的影响并利用同位素方法解析氮输出来源.结果表明，2015年湿季（7、8月）共11场降雨，产生的氮湿沉降负荷约达814.18 kg，氮沉降通量约为4.26kg·hm-2；干季（9月）共3场降雨，产生的湿沉降负荷约达155.58 kg，氮沉降通量为0.83 kg·hm-2，呈现出极大的季节变异性.通过对其中4场降雨过程进行动态分析发现，不同降雨强度对水体氮输出过程影响不同，4场降雨对流域水体的氮贡献量为16.94 kg.降雨径流氮输出负荷占流域水体氮输出负荷的比率为14.45%~64.84%，说明降雨对流域水体氮输出贡献很大.羊圈沟坝系流域δ15N变化范围较大，为-0.844‰~12.791‰，δ18O值在8.166‰~15.115‰范围内波动. |
| 英文摘要 |
| In this study,we wanted to explore the impacts of N wet deposition on N export and trace the N source by isotopic method through monitoring N wet deposition in Loess Plateau's Dam Watershed in alternating wet and dry seasons,through measuring N wet deposition,rainfall-runoff and base flow process and analyzing concentration change of different forms of N.The results showed that there were 11 rainfall events in the 2015 wet season,in which N wet deposition load reached 814.18 kg and N deposition flux was about 4.26 kg·hm-2,while there were three rainfall events in the 2015 dry season,in which N wet deposition load reached 155.58 kg and N deposition flux was 0.83 kg·hm-2,so it presented a great seasonal variability.By collecting the dynamic process of four rainfall events,we found that,different rainfall intensity had different influence on N export process.The contribution of N wet deposition of four rainfall events to N export in watershed was 16.94 kg.The ratio that N output load of rainfall and river in watershed N output load was 14.45%-64.84%,which showed that the contribution of rainfall to watershed N transport was big.The variation range of δ15 N in Loess Plateau's Dam Watershed was big,which was -0.844‰-12.791‰,and the δ18 O was within the range of 8.166 ‰-15.115 ‰ in the dam watershed. |
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