Mitigating soil greenhouse-gas emissions from land-use change in tropical peatlands

Conversion of tropical peat swamp forests to meet the demand for industrial plantations and agricultural production systems has triggered rapid and substantial carbon loss in the Asia-Pacific region. Various management practices have been designed to reduce carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) emissions from tropical peat soils after changes in land use. We conducted a meta-analysis using 506 paired observations on greenhouse-gas (GHG) emissions from peat soils under different land uses and the effects of management practices on emissions. As compared to peat swamp forest, other land uses had higher emissions of CO2 (heterotrophic respiration) and N2O from soils, whereas soil-based CH4 emissions were also increased but not significantly so. Raising the water table decreased CO2 emissions but increased N2O emissions; reducing nitrogen fertilizer inputs led to decreased CO2 and N2O emissions in oil-palm (Elaeis spp) plantations and cropping systems; and shading and growing cover crops decreased CO2 emissions. Practices such as these are needed for careful management of tropical peatlands, and additional measurements at appropriate spatial and temporal scales are required to guide future GHG mitigation strategies in tropical peatlands.