Seasonal changes of CO2, CH4 and N2O fluxes in relation to land-use change in tropical peatlands located in coastal area of South Kalimantan

Tropical peatland could be a source of greenhouse gases emission because it contains large amounts of soil carbon and nitrogen. However these emissions are strongly influenced by soil moisture conditions. Tropical climate is characterized typically by wet and dry seasons. Seasonal changes in the emission of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) were investigated over a year at three sites (secondary forest, paddy field and upland field) in the tropical peatland in South Kalimantan, Indonesia. The amount of these gases emitted from the fields varied widely according to the seasonal pattern of precipitation, especially methane emission rates were positively correlated with precipitation. Converting from secondary forest peatland to paddy field tended to increase annual emissions of CO2 and CH4 to the atmosphere (from 1.2 to 1.5 kg CO2-C m−2 y−1 and from 1.2 to 1.9 g CH4-C m−2 y−1), while changing land-use from secondary forest to upland tended to decrease these gases emissions (from 1.2 to 1.0 kg CO2-C m−2 y−1 and from 1.2 to 0.6 g CH4-C m−2 y−1), but no clear trend was observed for N2O which kept negative value as annual rates at three sites.