2021 Fiscal Year Annual Research Report
Utilization of Azolla in rice cultivation for environmental conservation and adaptation to climate change
| Project/Area Number |
21J14630
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| Research Institution | Yamagata University |
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Principal Investigator |
KIMANI Samuel Munyaka 山形大学, 農学部, 特別研究員(PD)
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| Project Period (FY) |
2021-04-28 – 2023-03-31
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| Keywords | Azolla / Dual crop / Methane / Nitrous oxide / Green manure / Paddy field |
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| Outline of Annual Research Achievements |
Azolla was either grown as a dual crop (Cover) or incorporated as green manure plus dual cropping (herein AGM + Cover) at the beginning of the experiment along with rice. Compared with the control (chemical fertilizer; NPK), NPK + Cover and AGM + Cover treatments did not influence cumulative CH4 emissions throughout the rice growth period. However, AGM + Cover treatment affected significant CH4 emissions at early, middle, and later rice growth stages by 141%, 25%, and 33%, respectively, compared with NPK + Cover treatment. These emissions were attributed to the readily available carbon substrate for methanogens following the incorporation of Azolla as green manure. Compared with NPK, NPK + Cover and AGM + Cover significantly increased N2O emissions by 646% and 816%, respectively, during the middle rice growth stage. No significant N2O emission differences were observed in the three treatments in the early or later rice growth stages. The higher N2O emissions from the middle rice growth stage were ascribed to high substrate availability from the dead Azolla by higher summer air temperature. AGM + Cover significantly decreased rice yield by 38% (NPK) and 35% (NPK + Cover), with no significant differences between NPK and NPK + Cover. This reduction was attributed to nitrogen immobilization from the incorporated Azolla during the early stage. Therefore, to ascertain the potential of Azolla in paddy fields to address environmental safety while sustaining yield, emphasis on the interaction of different application methods with various management practices is necessary.
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| Research Progress Status |
翌年度、交付申請を辞退するため、記入しない。
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| Strategy for Future Research Activity |
翌年度、交付申請を辞退するため、記入しない。
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Research Products
(2 results)
