Tauchnitz Nadine, Spott Oliver, Russow Rolf, Bernsdorf Sabine, Glaser Bruno, Meissner Ralph
a Department 25, Agro ecology and EU attended Monitoring , State Institute for Agriculture, Forestry and Horticulture Saxony-Anhalt , Bernburg , Germany.
Isotopes Environ Health Stud. 2015;51(2):300-21. doi: 10.1080/10256016.2015.1011634. Epub 2015 Feb 18.
Denitrification is well known being the most important nitrate-consuming process in water-logged peat soils, whereby the intermediate compound nitrous oxide (N(2)O) and the end product dinitrogen (N(2)) are ultimately released. The present study was aimed at evaluating the release of these gases (due to denitrification) from a nutrient-poor transition bog ecosystem under drained and three differently rewetted conditions at the field scale using a (15)N-tracer approach ([(15)N]nitrate application, 30 kg N ha(-1)) and a common closed-chamber technique. The drained site is characterized by a constant water table (WT) of -30 cm (here referred to as D30), while rewetted sites represent a constant WT of -15 cm, a constant WT of 0 cm (i.e. waterlogged), and an initial WT of 0 cm (which decreased slightly during the experiment), respectively, (here referred to as R15, R0, and R0(d), respectively). The highest N(2)O emissions were observed at D30 (291 µg N(2)O-N m(-2) h(-1)) as well as at R0d (665 µg N(2)O-N m(-2) h(-1)). At the rewetted peat sites with a constant WT (i.e. R15 and R0), considerably lower N2O emissions were observed (maximal 37 µg N(2)O-N m(-2) h(-1)). Concerning N(2) only at the initially water-logged peat site R0d considerable release rates (up to 3110 µg N(2)-N m(-2) h(-1)) were observed, while under drained conditions (D30) no N(2) emission and under rewetted conditions with a constant WT (R15 and R0) significantly lower N(2) release rates (maximal 668 µg N(2)-N m(-2) h(-1)) could be detected. In addition, it has been found that natural WT fluctuations at rewetted peat sites, in particular a rapid drop down of the WT, can induce high emission rates for both N(2)O and N(2).
反硝化作用是众所周知的淹水泥炭土中最重要的硝酸盐消耗过程，在此过程中，中间化合物一氧化二氮（N₂O）和最终产物氮气（N₂）最终会被释放出来。本研究旨在通过¹⁵N示踪法（施用¹⁵N硝酸盐，30 kg N ha⁻¹）和常用的密闭箱技术，在田间尺度上评估一个贫营养过渡沼泽生态系统在排水和三种不同再湿润条件下（由于反硝化作用）这些气体的释放情况。排水后的场地特点是地下水位（WT）恒定为-30 cm（此处称为D30），而再湿润场地的地下水位分别恒定为-15 cm、0 cm（即淹水）以及初始地下水位为0 cm（在实验过程中略有下降）（此处分别称为R15、R0和R0(d)）。在D30（291 μg N₂O-N m⁻² h⁻¹）以及R0(d)（665 μg N₂O-N m⁻² h⁻¹）处观察到最高的N₂O排放。在地下水位恒定的再湿润泥炭场地（即R15和R0），观察到的N₂O排放量要低得多（最大为37 μg N₂O-N m⁻² h⁻¹）。关于N₂，仅在最初淹水的泥炭场地R0(d)观察到相当高的释放速率（高达3110 μg N₂-N m⁻² h⁻¹），而在排水条件下（D30）没有N₂排放，在地下水位恒定的再湿润条件下（R15和R0），可以检测到明显较低的N₂释放速率（最大为668 μg N₂-N m⁻² h⁻¹）。此外，还发现再湿润泥炭场地的自然地下水位波动，特别是地下水位的快速下降，会导致N₂O和N₂的高排放率。
