Identifying nitrate dynamics in forest-agricultural ecosystem using triple oxygen isotopes

2016 Fiscal Year Final Research Report

• Project/Area Number: 26450486
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Environmental agriculture(including landscape science)
• Research Institution: National Agriculture and Food Research Organization (2016); National Institute for Agro-Environmental Sciences (2014-2015)
• Principal Investigator: Nakajima Yasuhiro 国立研究開発法人農業・食品産業技術総合研究機構, 農業環境変動研究センター 物質循環研究領域, 主任研究員 (10354086)
• Co-Investigator(Renkei-kenkyūsha): KOBAYASHI Masahiro 国立研究開発法人森林研究・整備機構, 森林研究部門立地環境研究領域, 土壌特性研究室長 (50353686) ; ITAHASHI Sunao 国立研究開発法人農業・食品産業技術総合研究機構, 農業環境変動研究センター, 企画連携室長 (80354009)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 硝酸イオン / 安定同位体 / 森林 / 農耕地 / 集水域 / 酸素同位体異常

Outline of Final Research Achievements

We identified the nitrate-nitrogen sources in forest area and rice paddy watershed in Mt Tsukuba. Water samples were collected from rainfall, soil water, hillside stream, drainage and river water. The stable isotopic compositions of nitrate, including the δ15N, δ18O and Δ17O, were analyzed.
The source of nitrate-nitrogen can be classified to three classes according to stable isotope profiles. First, the irrigation water showed middleδ15N, middle δ18O and low Δ17Ovalues. Second, the rainfall showed low δ15N, high δ18O, high Δ17O. Third, the soil water in forest area showed low δ15N, low δ18O, low Δ17O.

Free Research Field

環境農学