| 研究課題/領域番号 |
21KK0114
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| 研究種目 |
国際共同研究加速基金(国際共同研究強化(B))
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| 配分区分 | 基金 |
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| 審査区分 |
中区分40:森林圏科学、水圏応用科学およびその関連分野
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| 研究機関 | 京都大学 |
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研究代表者 |
EPRON Daniel 京都大学, 農学研究科, 特定教授 (60844305)
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| 研究分担者 |
東 若菜 神戸大学, 農学研究科, 助教 (20780761)
村瀬 潤 名古屋大学, 生命農学研究科, 教授 (30285241)
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| 研究期間 (年度) |
2021-10-07 – 2024-03-31
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| 研究課題ステータス |
交付 (2022年度)
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| 配分額 *注記 |
17,810千円 (直接経費: 13,700千円、間接経費: 4,110千円)
2023年度: 3,250千円 (直接経費: 2,500千円、間接経費: 750千円)
2022年度: 4,550千円 (直接経費: 3,500千円、間接経費: 1,050千円)
2021年度: 10,010千円 (直接経費: 7,700千円、間接経費: 2,310千円)
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| キーワード | Soil methane / Rubber plantation / Southeast Asia / Fertilisation / Soil nitrogen cycling / Soil microbial ecology / Soil methane uptake / Soil nitrogen / Hevea plantation / Tree water use |
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| 研究開始時の研究の概要 |
The project aims at characterising the effect of fertilisation on atmospheric methane by the soil, by testing two hypotheses: (1) fertilisation increases tree water use, reducing soil water content thus increasing the diffusion and the consumption of atmospheric; and (2) fertilization increases inorganic nitrogen and available phosphorus in the soil. Mineral nitrogen is known to inhibit methanotrophic activity when concentrations become high, while phosphorus may amplify or alleviate nitrogen inhibition.
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| 研究実績の概要 |
The proposal has been adopted in November 2021. Due to the Covid 19 and border restrictions, the first trip in Thailand for research activity was initially scheduled in March 2022 but postponed to September 2022. However, the project is progressing smoothly and the initial delay had no impact on it owing to the good preparation and coordination between the teams in Japan and Thailand. The motivation and engagement of our Thai partner is really impressive, and the organization of field trip and field work is awesome.
Two trips were organized this year, one in September 2022 to initiate the long-term measurements (methane flux, sap flow: 2 persons) and one in February 2023 for intensive measurements and samplings (microbiology, nitrogen cycling, soil nutrient capture: 4 persons).
The first 6 months of methane flux measurements showed a very clear effect of fertilization on the soil CH4 budget of this rubber plantation, not only reducing aerobic oxidation as we hypothesized but also increasing methane production in deeper soil layers.
Our Thai partners have successfully applied for a large “Reinventing KU” program which includes our JSPS project and through which two of us could be invited Professors in this new fiscal year.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
1: 当初の計画以上に進展している
理由
The project is progressing very smoothly compared to initially plan and despite the 6 months delay due to the Covid 19 situation.
We have installed an electric line to supply electricity to the experimental site in June. We have also asked our Thai colleagues to sample wood for us for anatomical studies that are now on going.
In September 2022, Wakana Azuma and Daniel Epron travelled to Thailand for two weeks to initiate methane flux measurement and train our Thai colleagues to perform the measurements every two weeks, which has been well done until now. We also installed 16 sap flow sensors and two data loggers to evaluate tree water use.
In February 2023, Wakana Azuma, Jun Murase and Makoto Shibata travelled to Thailand for 10 days, and Daniel Epron for an additional week (17 days). We performed intensive measurements of methane flux, maintain the sap flow sensors and add protection against thunderstorms and lightning, installed resin bags for capturing soil nutrients, perform nitrogen isotope labelling to estimate gross fluxes of nitrification, extract DNA for studying soil microbial communities (including the quantification of the abundances of the genes of the particulate CH4 monooxygenase methanotrophic bacteria and of the ammonia monooxygenase gene of the ammonia oxidizing bacteria and archaea) and collect soil samples for incubation to determine the potential of soil methane oxidation.
These two field trips were preceded by two online meetings between the Japanese and the Thai teams to prepare the field and laboratory work.
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| 今後の研究の推進方策 |
Two one-week short travels to Thailand have been planned for this fiscal year for the PI, mainly devoted to the management of the resin bags installed for capturing soil nutrients (ammonium, nitrate, phosphate and potassium mainly) at the time fertilizers are applied to the site.
In August 2023, four of us (Wakana Azuma, Jun Murase, Makoto Shibata and Daniel Epron) will travel for at least 10 days to perform intensive field studies, including the estimation of gross fluxes of nitrification using nitrogen isotope labelling, extraction DNA for studying soil microbial communities and collection soil samples for incubation to determine the potential of soil methane oxidation. It will be similar to what we did last year in February during the dry season but this time it will be during the wet season.
A fourth trip is planned in February 2024 to complete the measurements of soil methane flux, uninstall the sap flow sensors and data loggers. Between each of these trips, the Thai partner will continue to measure soil methane flux every two weeks and to take care about the sap flow sensors.
From September 2023, we will have the results of one-year measurement of soil methane flux and tree water use as well as the results of gross fluxes of nitrification and soil microbial communities at two contrasting seasons. We will be able to start writing papers and presenting results in conferences. We will also elaborate plan with our Thai partners for the continuation of this collaborative effort.
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