Soil‐atmosphere exchange potential of NO and N2O in different land use types of Inner Mongolia as affected by soil temperature, soil moisture, freeze‐thaw, and drying‐wetting events
Soil‐atmosphere exchange potential of NO and N2O in different land use types of Inner Mongolia as affected by soil temperature, soil moisture, freeze‐thaw, and drying‐wetting events
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内蒙古不同土地利用类型土壤-大气NO和N2O交换潜力受土壤温度、土壤湿度、冻融、干湿事件影响
DOI：
10.1029/2009jd013528
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发表时间：
2010-09
影响因子：
4.4
通讯作者：
刘春岩
中科院分区：
文献类型：
--
作者：
刘春岩
亚洲大陆草原降水和温度的变化可能影响控制n -微量气体生物圈-大气交换的土壤物理、化学和生物过程。这些变化包括影响中国和蒙古大草原地区的区域荒漠化、全球变暖和强厄尔尼诺事件。该区域如此之大，以至于可能会对全球温室气体平衡产生反馈。本文研究了内蒙古锡林河流域典型土地利用/覆被类型中土壤湿度和温度的变化，特别是干-复湿和冻融事件对大型完整土壤芯中一氧化氮（NO）和氧化亚氮（n2o）通量的影响。这些土芯在不同的温度（-10至15°C）和模拟降雨（25、45和65毫米）条件下孵育。研究了典型草原、山地草甸、沙丘和湿地土壤在干-复湿和冻融过程中NO和n2o排放的变化规律。土壤CO 2排放和土壤大气N 2 O浓度的变化趋势表明，土壤湿润和融化后基质有效性高，微生物活性恢复快，导致气体通量高。在整个温度范围内，除沼泽土壤n2o排放外，所有土壤的NO和n2o通量均与土壤温度呈正指数关系。土壤温度和土壤湿度的组合解释了观测到的单个土壤NO（高达74-90%）和n2o（高达67-89%）通量的大部分变化。不同土地利用/覆被类型间NO排放的空间差异可以用土壤有机碳和pH值的差异来解释，而n2o通量的空间变化主要与土壤微生物生物量的差异相关。在控制条件下的孵育基础上，按调查区域不同土地利用/覆盖类型的面积范围加权，估计NO的年平均通量为~3.9±1.1 kg N ha -1 yr -1， n2o的年平均通量为0.53±0.20 kg N ha -1 yr -1。值得注意的是，我们的测量是使用没有植被覆盖的土壤岩心进行的，这可能导致对n -微量气体通量的高估。然而，我们的研究结果表明，很少确定的NO形成似乎是半干旱草原N循环的重要途径，这对这些地区发生的气候变化，特别是干湿循环和冻融循环的强度和频率的增加高度敏感。
[1] Changes in precipitation and temperature in Asian continental steppelands may affect soil physical, chemical and biological processes that control the biosphere-atmosphere exchange of N-trace gases. The changes include regional desertification, global warming and strong El Nino events that impact the large steppe land area in China and Mongolia. The area is so large that feedbacks to the global greenhouse gas balance may occur. In this study we investigated how changes in soil moisture and temperature, and especially drying-rewetting and freeze-thaw events, affect nitric oxide (NO) and nitrous oxide (N 2 O) fluxes from large intact soil cores taken from representative land use/cover types in the region of the Xilin River catchment, Inner Mongolia. These soil cores were incubated under varying conditions with respect to temperature (ranging from -10 to 15°C) and simulated rainfall (25, 45 and 65 mm). Following drying-rewetting and freeze-thaw transitions, we observed pulses of NO and N 2 O emissions from the soils of typical steppe, mountain meadow, sand dune and marshland. A comparable trend in soil CO 2 emissions and soil air N 2 O concentrations indicated that the high substrate availability and rapid recovery of microbial activity after soil wetting and thawing resulted in high gas fluxes. Across the whole temperature range, NO and N 2 O fluxes from all soils, except for N 2 O emissions from marshland soils, showed a positive exponential relationship with soil temperature. A combination of soil temperature and soil moisture explained most of the observed variations in NO (up to 74-90%) and N 2 O (up to 67-89%) fluxes for individual soils. Spatial differences in NO emissions between land use/cover types could be explained by differences in soil organic carbon and pH, whereas spatial variations of N 2 O fluxes were primarily correlated with differences in soil microbial biomass. On the basis of the incubation under controlled conditions, the average annual flux, weighted by the areal extent of the different investigated land use/cover types in the region, was estimated at ~3.9 ± 1.1 kg N ha -1 yr -1 for NO and 0.53 ± 0.20 kg N ha -1 yr -1 for N 2 O, respectively. It is noteworthy that our measurements were conducted using soil cores without a vegetation cover, which probably resulted in an overestimation of N-trace gas fluxes. However, our results indicate that the rarely determined NO formation appears to be a significant pathway in the N cycle of semiarid steppe, which is highly sensitive to the climatic change taking place in these regions, especially an increase in intensity and frequency of drying-wetting and freeze-thaw cycles.
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影响因子：
3.5
作者：
D. Mummey;Jeffrey L. Smith;G. Bluhm
通讯作者：
D. Mummey;Jeffrey L. Smith;G. Bluhm
DOI：
10.1023/a:1013134500845
发表时间：
2001-09
期刊：
Water, Air and Soil Pollution: Focus
影响因子：
--
作者：
Saskia M. van Dijk;F. Meixner
通讯作者：
Saskia M. van Dijk;F. Meixner
影响因子：
2.9
作者：
Akiyama, H;McTaggart, IP;Scott, A
通讯作者：
Scott, A
影响因子：
--
作者：
Zhi-Ping Wang;Xingguo Han;Linghao Li;Q. Chen;Y. Duan;W. Cheng
通讯作者：
Zhi-Ping Wang;Xingguo Han;Linghao Li;Q. Chen;Y. Duan;W. Cheng
DOI：
--
发表时间：
1991
期刊：
--
影响因子：
--
作者：
E. Davidson;J. Rogers;W. Whitman
通讯作者：
E. Davidson;J. Rogers;W. Whitman