| Co-Investigator(Kenkyū-buntansha) |
INOUE Takashi Hokkaido University, Graduate School of Agriculture, Associate Professor, 大学院・農学研究科, 助教授 (30203235)
YONEBAYASHI Koyo Kyoto Prefectural University, Graduate School of Agriculture, Professor, 農学部, 教授 (00046492)
OKAZAKI Masanori Tokyo University of Agriculture and Technology, Graduate School of Bio-Applications and Systems Engineering, Professor, 大学院・生物システム応用科学研究科, 教授 (00092479)
TOYOTA Koki Tokyo University of Agriculture and Technology, Graduate School of Bio-Applications and Systems Engineering, Associate Professor, 大学院・生物システム応用科学研究科, 助教授 (30262893)
KURAMOCHI Kanta Hokkaido University, Graduate School of Agriculture, Asistant Professor, 大学院・農学研究科, 助手 (00225252)
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| Research Abstract |
Tropical peatland is important for net carbon (C) storage in the global land surface, but it is also believed to be a major emission source of CH4.Land resource exploitation and burning of peat increases C release from the peatland, and thus contributes to overall global warming. In order in discern the magnitude of agricultural and fire impacts in tropical peatlands on global warming, ground surface emissions of three major greenhouse gases (GHG), CO2, CH4 and N2O, were measured in various ecosystems including forests and agricultural fields, as well as fire-affected lands in Karampangan zone, near Plangka Raya, from 2001 to 2003.After forest burning, the GWP decreased in 32-42% of the GWP from the natural forest, with 99% of the GWP occurring from CO2 emission. However, no trees could absorb the CO2, so the CO2 emissions went directly to the atmosphere.CH4 was emitted from the burned peatland, while CH4 uptake was observed in both the natural and regenerated forests.
The GWP in the agricultural field was approximately 2 times larger than that from the natural forest. CO2 emission in the agricultural field was about 5 times larger than that in Japanese crop fields and accounted for 50-90% of the GWP. The remaining GWP was contributed by N2O emission. The N2O emission was considerably high, accounting for 4-23% of the nitrogen (N) application rate of 626 kg N ha1 yr-1.This is probably due to high peat decomposition and high nitrification enhanced by high pH and high exchangeable Ca content us the agricultural fields.
Magnitude of forest fire impact on global warming was much higher than agricultural impact. But nitrogen application in agricultural field, which may accelerate peas decomposition, enhanced N2O emission and deduced CH4 uptake.
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