Historical soil drainage mediates the response of soil greenhouse gas emissions to intense precipitation events
Historical soil drainage mediates the response of soil greenhouse gas emissions to intense precipitation events
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DOI：
10.1007/s10533-019-00544-x
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发表时间：
2019-01
期刊：
影响因子：
4
通讯作者：
Alexander H. Krichels;E. DeLucia;R. Sanford;J. Chee-Sanford;Wendy H. Yang
中科院分区：
文献类型：
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作者：
Alexander H. Krichels;E. DeLucia;R. Sanford;J. Chee-Sanford;Wendy H. Yang
由于气候变化，美国中西部的降水事件正在加剧。这导致排水不良的高地土壤被洪水淹没，从而通过改变一氧化二氮 (N 2 O) 和二氧化碳 (CO 2) 等温室气体 (GHG) 排放来反馈气候变化。本研究的目的是确定土壤排水历史是否影响土壤温室气体排放对降雨事件的响应。为此，我们测量了伊利诺伊州厄巴纳农田在大雨前后排水不良 (PD) 和排水良好 (WD) 土壤中的 N 2 O 和 CO 2 通量。我们还进行了一项实验室实验，将土壤排水历史的影响与当代积水的影响分开。最后，我们利用稳定同位素技术来测量总 N 2 O 动态并确定硝化菌和反硝化菌对净 N 2 O 通量的贡献。我们发现，WD 土壤积水会导致 N 2 O 净流出脉冲，这是由反硝化菌刺激 N 2 O 总产量引起的。相比之下，PD 土壤仅在大降雨期间具有较高的净 N 2 O 流出量，并且在积水后总 N 2 O 产生受到抑制。在实验室条件下，PD 土壤的土壤 CO 2 流出量更大，但自养呼吸掩盖了现场的这一趋势。土壤温室气体排放是不同的当代积水状况以及历史土壤排水的结果，表明历史土壤氧化还原机制调节土壤温室气体动态以响应降水。这些土壤排水遗留影响对于预测土壤温室气体对气候变化的反馈影响可能很重要。
Precipitation events are increasing in intensity in the Midwestern US due to climate change. This is resulting in flooding of poorly-drained upland soils, which can feed back on climate change by altering greenhouse gas (GHG) emissions, including nitrous oxide (N 2 O) and carbon dioxide (CO 2). The objective of this study was to determine if soil drainage history affects the response of soil GHG emissions to rain events. To do this, we measured N 2 O and CO 2 fluxes from poorly-drained (PD) and well-drained (WD) soils in an agricultural field in Urbana, Illinois before and after large rain events. We also performed a lab experiment to separate effects of soil drainage history from contemporary effects of ponding. Finally, we utilized stable isotope techniques to measure gross N 2 O dynamics and to determine the contributions of nitrifiers and denitrifiers to net N 2 O fluxes. We found that ponding of WD soils led to pulses of net N 2 O efflux caused by stimulation of gross N 2 O production by denitrifiers. In contrast, PD soils had high net N 2 O effluxes only between large rain events, and gross N 2 O production was inhibited following ponding. Soil CO 2 efflux was greater from PD soils under lab conditions, but autotrophic respiration obscured this trend in the field. Soil GHG emissions were a result of different contemporary ponding status as well as historical soil drainage, suggesting that historical soil redox regimes regulate soil GHG dynamics in response to precipitation. These soil drainage legacy effects are likely important in predicting soil GHG feedback effects on climate change.