| 模拟氮沉降对内蒙古克氏针茅草原N2O排放的影响 |
| 摘要点击 2145 全文点击 974 投稿时间：2015-11-20 修订日期：2015-12-29 |
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| 中文关键词 N2O排放 温带草原 克氏针茅 氮沉降 温室气体 |
| 英文关键词 N2O emission temperate steppe Stipa krylovii N deposition greenhouse gas |
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| 中文摘要 |
| 随着工农业和社会的快速发展,我国成为全世界氮沉降最高的国家之一,温带草原地区的氮沉降水平局部可能超过3g·(m2·a)-1.为研究氮沉降对我国典型草原生态系统氮循环的影响,在内蒙古太仆寺旗的克氏针茅草原,对土壤氧化亚氮(N2O)的排放进行了为期1 a测定; 同时,对该天然草地施加NaNO3-N以模拟氮沉降增加,进行了6个水平:CK(对照)、N2[2 g·(m2·a)-1]、N5[5 g·(m2·a)-1]、N10[10 g·(m2·a)-1]、N25[25 g·(m2·a)-1]和N50[50 g·(m2·a)-1]的野外控制实验.结果表明,在自然氮沉降条件下,该生态系统N2O的排放主要取决于土壤含水量和土壤温度,通过参数拟合估计全年N2O-N排放量为0.10 g·(m2·a)-1,约为当地氮沉降量的3%.而提高氮沉降可以显著提高N2O的排放,特别是在高氮处理下(N25和N50),N2O的年排放量与模拟氮沉降量呈线性关系.我国温带典型草原较高的温室气体N2O排放值得关注. |
| 英文摘要 |
| With fast development of industry, agriculture and society, very high N deposition occurs in China. N deposition has exceeded 3 g· (m2·a)-1 in some areas of temperate steppes, which is a significant part of the Eurasia grassland, but may possibly be sensitive to N deposition. To study the effect of N deposition on N cycling in typical temperate steppe, N2O emissions were measured in a Stipa krylovii steppe in Inner Mongolia for a whole year. A field control experiment of simulated N deposition (by NaNO3 addition) was also carried out at 6 dose levels, CK (control), N2 [2 g·(m2·a)-1], N5 [5 g·(m2·a)-1], N10 [10 g·(m2·a)-1], N25 [25 g·(m2·a)-1], and N50 [50 g·(m2·a)-1]. The results showed that the natural N2O-N emission flux was 0.10 g·(m2·a)-1, accounting for about 3% of the total N deposition, and much depended on soil water content and soil temperature under ambient N deposition. In addition, enhanced N deposition might significantly increase N2O emission, especially at very high N doses (N25 and N50 treatments). The annual N2O emission flux showed a linear relationship with the N addition. Greater attention should therefore be paid to the relatively high N2O emission in the typical temperate steppe in China. |
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