Impact of Peat Fire on the Soil and Export of Dissolved Organic Carbon in Tropical Peat Soil, Central Kalimantan, Indonesia

Tropical peatlands play an important role in the global carbon cycle, and therefore, their stability has important implications for climate change. In this study, we evaluated the effect of fire on the physical, chemical, and biological properties of peat soils in Indonesia for three years following exposure to fire. The results of the thermal analysis suggest that the organic matter contents of surface soils significantly decreased because of peat fires and that charred materials were produced in the subsurface layer of the burned soils. The atomic ratios of the burned soils and the thermally treated samples indicate that the Indonesian peat soils were dehydrated by these low-severity fires. The microbial abundance and phosphatase activity in the burned soils significantly decreased compared to those of the unburned soils. Leaching of the dissolved organic carbon (DOC) concentration from the burned soils is lower than that from the unburned soils. The obtained laboratory results indicate that the concentration of the leached DOC increased drastically after heat treatments near the ignition temperature. It was seen that the denaturation of the soil organic matter caused by the heat from the fire accelerates the exodus of organic carbon in peatlands, which contain huge accumulations of carbon.