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 (292KB)
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71,814,000 Yen** (FY1998; 24,522,000 Yen)
The purpose of this study is to evaluate the influence of land-use/cover change in tropical Asia on the greenhouse gas emissions. An intensive field experiment has started in humid tropical forests In Jambi, Sumatra of Indonesia since January 1997, in collaborating with BIOTROP-GCTE-IC-SEA of Indonesia. The three sites of primary and logged-over forests, a site clear-cut and bumed before one year, and a rubber plantation site In a small holder were selected to measure the fluxes of carbon dioxide(CO2), methane(CH4), and nitrous oxide(N2O) from the soil surface to the atmosphere. At all the sites, CO2 and N2O were emitted from the soil to the atmosphere, while CH4 was absorbed to the surface soil except for one site. An incubation experiment was also performed to measure the potential of emission/absorption of greenhouse gases by using the soils at the field sites. The CO2 and N2O emission rates were highest in the surface soil (a depth of 0-5cm) in comparison with those in the deeper soil (a depth of 10-25 cm), while the uptake rate of CH4 Was lowest in the surface soil. Both of field and incubation experiments demonstrated that the emission/absorption rates of greenhouse gases were significantly affected after deforestation, and suggest that those rates would be recovered slowly after plantations to the same level as before deforestation. The first field measurement of greenhouse gas emission in peat wetlands was carried out in Banjalmasin, Kalimantan, in Dec. 1998. The N2O flux to the atmosphere was very high at a site where the concentration of NH4+-N was high in the soil possibly due to fertilisation, while the CH4] fluxes to the atmosphere at all four sites were low compared with in the Amazon.
land-use/cover change, humid tropical forests, peat wetlands. greenhouse gases, emission