Groundwater level effects on greenhouse gas emissions from undisturbed peat cores

作者：Erne Blondeau, G.L. Velthof, M. Heinen, R.F.A. Hendriks, Anneke Stam, J.J.H. van den Akker, Monne Weghorst, Jan Willem van Groenigen · 发表于：Geoderma · 年份：2024 · DOI：10.1016/j.geoderma.2024.117043 · 被引用次数：8 · 研究领域：Peatlands and Wetlands Ecology、Integrated Water Resources Management、Landfill Environmental Impact Studies

• Rewetting above −20 cm decreased CO 2 emissions, but caused strong N 2 O emissions. • CO 2 from peat oxidation showed different responses to drying and rewetting. • Production of CO 2 and N 2 O occurred mostly in the top soil. • Variable soil moisture at a −20 cm groundwater level creates a risk for N 2 O peaks. • Oxidation was estimated to contribute 66 to 79% to vertical displacement. Peat soils store a large part of the global soil carbon stock, which can potentially be lost when they are drained and taken into cultivation, resulting in CO 2 emission and land subsidence. Groundwater level (GWL) management has been proposed to mitigate peat oxidation, but may lead to increased emissions of nitrous oxide (N 2 O) and methane (CH 4 ). The aim of this experiment was to study trade-offs between greenhouse gas emissions from peat soils as a function of GWL. We incubated 1 m deep, 24 cm diameter undisturbed bare soil cores, after removal of the grass layer, from three contrasting Dutch grassland peat sites for 370 days at 16 °C. The cores were subjected to drying-wetting cycles, with the GWL varying between near the soil surface to 160 cm below the surface. We measured gas fluxes of CO 2 , N 2 O and CH 4 from the soil surface, extracted pore water for DOC and mineral nitrogen analysis, and measured soil hydraulic and shrinkage characteristics. Emissions of CO 2 increased after lowering the GWL, but showed different GWL-response curves during rewetting of the soil. On average, hi...