Reduction in carbon dioxide and methane production of tropical peatlands due to coal fly-ash application

Tropical peatlands with very high organic carbon (C) contents have the potential to be a source of carbon dioxide (CO2) and methane (CH4) production. Therefore, the management of tropical peatlands is essential to prevent peat decomposition and to reduce the production of CO2 and CH4. We added different amounts of coal fly-ash (CFA) (0, 25, 50, 75, 100 and 125 Mg ha−1) to tropical peats in a laboratory study to quantify changes in CO2 and CH4 production in response to the application of CFA. The amounts of CO2 and CH4 produced by the mixtures of peats and CFA over 90 days were monitored on weekly basis. Peat pH, concentrations of hot-water soluble C, calcium and iron were also measured at the end of incubation period. Results of study revealed that the application of CFA up to 50 Mg ha−1 did not change the production of CO2 and CH4, while the application of CFA by 50–125 Mg ha−1 reduced 12–24% of CO2 and 9–15% of CH4. The decrease in the production of CO2 and CH4 due to the relatively high amount of CFA application was related to the decrease in the amount of hot soluble organic C and the increase in the concentrations of Ca and Fe. This study demonstrates the potential of CFA as waste materials from coal processing of power plants in reducing CO2 and CH4 emissions of tropical peatlands.