Does agricultural use of tropical peat soil really accelerate peat decomposition?

Research Project

Project/Area Number	15K14903
Research Category	Grant-in-Aid for Challenging Exploratory Research
Allocation Type	Multi-year Fund
Research Field	Environmental agriculture(including landscape science)
Research Institution	Nagoya University
Principal Investigator	WATANABE Akira 名古屋大学, 生命農学研究科, 教授 (50231098)
Project Period (FY)	2015-04-01 – 2017-03-31
Project Status	Completed (Fiscal Year 2016)
Budget Amount *help	¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000) Fiscal Year 2016: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000) Fiscal Year 2015: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Keywords	環境調和型農林水業 / 土壌圏現象 / 熱帯農業 / 泥炭 / 環境調和型農林水産 / 有機物分解 / 熱帯泥炭
Outline of Final Research Achievements	Tropical peatland is one of the remaining land resources, and an acceleration of the mineralization of vast amount of soil organic carbon (SOC) stored as peat under agricultural use accompanying drainage has been concerned. On the other hand, the lack of significant change in the rate of SOC mineralization due to landuse change suggested the presence of considerable amount of SOC stabilized. To confirm the existence of such SOC, forest and cultivated peat soils collected in Sarawak, Malaysia, were analyzed. Recalcitrant humic substances, based on the degree of darkening, were not detected in the fractionation humic acids. Black carbon content estimated by nitric acid oxidation was less than 1% of total SOC. 13C NMR spectra determined before and after irradiation did not differ, indicating similar sensitivity to photo-degradation among SOC components. Thus, the presence of persistent SOC in tropical peat soil was not proven in this study.