Fertilization effects on atmospheric methane uptake by a rubber tree plantation in Thailand: a direct microbial inhibition or an indirect stimulation by higher tree water use?

2023 Fiscal Year Final Research Report

• Project/Area Number: 21KK0114
• Research Category: Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 40:Forestry and forest products science, applied aquatic science, and related fields
• Research Institution: Kyoto University
• Principal Investigator: EPRON Daniel 京都大学, 農学研究科, 教授 (60844305)
• Co-Investigator(Kenkyū-buntansha): 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)
• Project Period (FY): 2021-10-07 – 2024-03-31
• Keywords: Soil methane / Rubber plantation / Southeast Asia / Fertilization / Nitrogen cycling / Microbial ecology

Outline of Final Research Achievements

The objective of this joint international project was to have a deep insight into the effect of fertilization on atmospheric CH4 uptake by the soil of rubber plantations because of its positive role in mitigating climate change. Two types of interaction between fertilization and CH4 uptake are expected. Our first hypothesis that fertilization increases the diffusion of CH4 in the soil due to a higher rate of transpiration of trees in fertilized plots, promoting its oxidation, was rejected. Our second hypothesis was that fertilization increases inorganic nitrogen and available phosphorus in the soil, which inhibits methanotrophic activity when concentrations become high, was confirmed. In addition, we showed that fertilization also enhanced methanogenesis.

Free Research Field

Forest Science

Academic Significance and Societal Importance of the Research Achievements

Fertilization inhibited methanotrophic activity and stimulated methanogenesis, decreasing the strength of the CH4 sink of a rubber plantation, and
turns the plantation from a sink to a source of CH4 at the high rate of fertilizer application. The loss of soil CH4 uptake should be evaluated