Results of observations in Central Kalimantan, Indonesia clearly indicate that land use changes caused by drainage, fire, and agricultural practices change the methane (CH4) and nitrous oxide (N2O) emissions from tropical peatlands significantly. The CH4 emissions were higher in burned area and croplands than in natural forests. The N2O emissions were considerably higher in croplands than in natural forests, although there were no significant differences in N2O emissions between burned areas and natural forests. In croplands, the N2O flux was significantly correlated with the carbon dioxide (CO2) flux. However, the CO2 flux in croplands was not correlated with microbial biomass carbon (MBC), while this was significantly correlated in forests. These results indicate that agricultural land use of tropical peatlands varied the controlling factors of the greenhouse gas emissions through microbial activities. Peat fires were also a significant source of CH4 and N2O as well as CO2. Linear correlations of the concentrations of CH4, N2O, and also carbon monoxide (CO) to CO2 indicated that the molar ratios of CO, CH4 and N2O to CO2 in the gas emissions through peat combustion are 0.382, 0.0261 and 0.000156, respectively.
