Carbon cycle processes of tropical peatland: Interdisciplinary evaluation of development impact

2018 Fiscal Year Final Research Report

• Project/Area Number: 16H05784
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 海外学術
• Research Field: Plant nutrition/Soil science
• Research Institution: Kitasato University
• Principal Investigator: Maie Nagamitsu 北里大学, 獣医学部, 講師 (00453514)
• Co-Investigator(Kenkyū-buntansha): 渡邉 彰 名古屋大学, 生命農学研究科, 教授 (50231098) ; 池永 誠 鹿児島大学, 農水産獣医学域農学系, 准教授 (70511822) ; 落合 博之 北里大学, 獣医学部, 講師 (90440156)
• Research Collaborator: TAKAMATSU RIEKO ; TANJI HAJIME ; MELLING LULIE
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 熱帯泥炭 / 油ヤシプランテーション / 炭素循環 / 分解速度 / 分解プロセス / 持続的利用

Outline of Final Research Achievements

Impact of the development of tropical peat swamp forest into oil palm plantation (OPP) was investigated in terms of decomposition rates and processes of tropical peat under OPP management, and the factors affecting to it. Our results showed: 1) grain size of peat becomes smaller as the decomposition proceeds, which, depending on peat type, suppresses decomposition by negative feedback. 2) Water content influences bidirectionary on peat decomposition: as the water content increases, oxygen diffusion rate lowers on one hand, but mobility of substrates and enzymes increases on the other hand. 3) Compaction of peat suppresses oxygen diffusion rate, resulting in the suppression of peat decomposition. 4) Microbial community structure of tropical peat under primary forest is similar, while some proportional variation exists, among different forest types. 5) Precipitation amount during wet-season may influence decomposition of peat in OPP during ensuing dry season.

Free Research Field

生物地球化学

Academic Significance and Societal Importance of the Research Achievements

本研究の成果は，地球規模の炭素バランスに大きく影響を及ぼす熱帯泥炭土の，開発に伴う炭素循環プロセスの変化とそのメカニズム，および，熱帯泥炭土の持続的農業利用を成功させるための圃場管理に関する貴重な基礎的知見となるものである。熱帯泥炭は油ヤシプランテーション開発に伴い急速に分解すると一般に考えられてきたが，適切な泥炭のタイプを，適切な管理下において利用することにより，分解速度を低く保つことができる可能性を示した意義は大きいと考えられる。