Soil characteristics controlling nitrous oxide emissions of tropical peatlands

Abstract

Emission of nitrous oxide (N2O) from peatlands contributes very significantly to the world global warming, although the factors controlling N2O emissions from peatlands are not yet clear. This study aimed to determine peat characteristics controlling N2O emissions in peatlands. N2O emissions and several soil characteristics (pH, electrical conductivity, height of water table, water-filled pore space, decomposition degree of peats, bulk density, organic carbon, total nitrogen, and concentrations of ammonium and nitrate) were observed in peatlands with different crops and land-uses: lettuce, spring-onion, albizia, shrubs-peat, and burned-peats. Correlation-regression analyses were employed to quantify peat properties influencing the rates of N2O emission from peatlands. The results of the study showed that N2O emissions varied based on the type of crops/land-uses, in which peats used for crop cultivation had higher N2O emissions than others. The results of the analysis also revealed that N2O emissions of peat were controlled by variables related to water contents and the contents of NH4+ and NO3-. In peats with relatively similar NH4+ and NO3- contents, N2O emissions were determined by variables related to water contents (height of water table and volumetric water contents). The result of this study shows the need for water and peat fertility management for the mitigation of N2O emission from peatlands. Thus, managing the availability of nitrogen by using biological fertilizers to reduce the amounts of inorganic nitrogen fertilizers is required to reduce N2O emissions without decreasing crop yields in peatlands.