Fertilizer-induced fluxes dominate annual N2O emissions from a nitrogen-rich temperate fen rewetted for paludiculture
Fertilizer-induced fluxes dominate annual N2O emissions from a nitrogen-rich temperate fen rewetted for paludiculture
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DOI：
10.1007/s10705-019-10012-5
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发表时间：
2019-07
影响因子：
3.1
通讯作者：
Tanka P. Kandel;Sandhya Karki;L. Elsgaard;P. Lærke
中科院分区：
文献类型：
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作者：
Tanka P. Kandel;Sandhya Karki;L. Elsgaard;P. Lærke
再润湿的泥炭地对温室气体一氧化二氮 (N2O) 的来源微不足道。然而，用于沼泽养殖的再湿泥炭地可能需要施氮 (N) 肥，这可能会造成反硝化和 N2O 排放的热点。在这项研究中，我们使用静态室连续两年测量了富含氮的河岸沼泽的 N2O 排放量。田间试验包括在不同程度的人工再润湿下种植芦苇金丝雀草（Phalaris arundinaceaL.）的并排地块。这些处理被定义为对照、半淹没和淹没条件，分别对应于土壤表面以下 9、3 和 1 厘米的 2 年加权平均地下水位 (GWT) 深度。作物每年施肥和收获两次（160 kg N ha−1year−1，分两等份）。每次施肥事件后，所有处理均观察到大量 N2O 排放，导致第一年累计年排放量为 3.2–6.0 kg N2O–N ha−1，第二年累计年排放量为 1.8–4.2 kg N2O–N ha−1。受精期以外的排放量可以忽略不计。第一年各处理的年 N2O 排放量相似（P>0.05），而对照处理第二年的排放量最低。在所有处理中，收获的生物量中的氮去除量（197–218 kg N ha−1year−1）超过了肥料氮，表明栽培生物量利用了来自泥炭土的大量矿化氮。总体而言，结果表明，当富含氮的河岸泥炭地保持高 GWT 时，尽管背景土壤排放量较低，但肥料引起的 N2O 排放量可能很高。
Rewetted peatlands are weak to negligible sources of the greenhouse gas nitrous oxide (N2O). However, rewetted peatlands in use for paludiculture may require nitrogen (N) fertilization potentially creating hot moments for denitrification and N2O emissions. In this study, we measured N2O emissions from an N-rich riparian fen for two consecutive years using static chambers. The field experiment included side-by-side plots cultivated with reed canary grass (Phalaris arundinaceaL.) under different degrees of manipulated rewetting. The treatments were defined as control, semi-flooded and flooded conditions corresponding to 2-year weighted mean groundwater table (GWT) depths of 9, 3 and 1 cm below soil surface, respectively. The crop was fertilized and harvested twice a year (160 kg N ha−1year−1in two equal splits). Large N2O emissions were observed from all treatments after each fertilization event, which contributed to cumulative annual emissions of 3.2–6.0 kg N2O–N ha−1in the first year and 1.8–4.2 kg N2O–N ha−1in the second year. Emissions outside the fertilization periods were negligible. Annual N2O emissions were similar (P> 0.05) among the treatments in the first year whereas control treatments had the lowest emissions in the second year. Nitrogen removal in harvested biomass (197–218 kg N ha−1year−1) exceeded the fertilizer N in all treatments, indicating that the cultivated biomass utilized substantial amounts of mineralized N from the peat soil. Overall, the results indicate that fertilizer-induced N2O emissions can be high although background soil emissions are low when high GWT is maintained on N-rich riparian peatland.