Temporal variation of stable isotopic values for dissolved nitrogen compounds in paddy water environment
Temporal variation of stable isotopic values for dissolved nitrogen compounds in paddy water environment
复制标题
稻田水环境中溶解氮化合物稳定同位素值的时间变化
DOI：
10.53747/jnst.v9i3.44
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
K. Nishida
中科院分区：
文献类型：
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作者：
M. Saiki;T. Do;Thuy Hai Cao Thi;Takashi Nakamura;Thao Ta Thi;K. Nishida
越南是全球第二大稻米出口国，近年来肥料施用量迅速增加。在稻田里过度使用化肥是造成水体污染的主要原因。本研究旨在通过对越南某稻田氮素浓度和稳定同位素值的观测，了解氮素浓度和稳定同位素值随时间的变化规律，为氮素的来源和过程研究提供基础和有用的线索。调查结果表明，随着浓度的变化，积水中铵态氮和硝态氮的δ 15 N值变化剧烈，分别为-3.6‰ ~ 17.2‰和-18.2‰ ~ 8.5‰。本研究表明，水稻田氮素的主要来源不仅是化肥，而且灌溉水也是氮素的主要来源。此外，根据时间同位素变化推测了微生物硝化和反硝化作用。
Vietnam is the second-largest rice exporter worldwide and the amount of applied fertilizer is increasing rapidly in recent years. Overuse of chemical fertilizers in the paddy fields strongly contributes to the pollution of water bodies. This study aimed to understand the temporal variation of nitrogen concentrations and stable isotope values as environmental tracers based on the observed data in a selected paddy field in Vietnam, which provides basic and useful clues for tracing sources and identifying processes of nitrogen. The results from the field survey showed that , in accordance withthe changes in concentrations, δ15N values of ammonium and nitrate in ponded water drastically varied from -3.6‰ to 17.2‰ and from -18.2‰ to 8.5‰, respectively. The present study implied that not only chemical fertilizers but also irrigation water was the major source of nitrogen into the paddy. In addition, microbiological nitrification and denitrification were presumed based on the temporal isotopic variations.