Soil degradation determines release of nitrous oxide and dissolved organic carbon from peatlands

Carbon (C) and nitrogen (N) release from peatlands are closely related to water management and soil degradation. However, peat degradation has not been explicitly accounted for when estimating national greenhouse gas inventories. Here, we assembled a comprehensive dataset covering European, Russian and Canadian peatlands and introduced soil bulk density (BD) as a proxy for peat degradation to estimate nitrous oxide (N2O) and dissolved organic carbon (DOC) release. The results show that physical and biogeochemical properties of peat are sensitive to soil degradation. The BD is superior to other parameters (C/N, pH) to estimate annual N2O emissions and DOC pore water concentrations. The more a peat soil is degraded, the higher the risk of air/water pollution in peaty landscapes. Even after rewetting, highly degraded soils may exhibit high N2O release rates. The estimated annual N2O-N emissions from European, Russian and Canadian degraded peatlands sum up to approximately 81.0 Gg. The derived BD-based functions can assist in computing global matter fluxes from peatlands.