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Conference abstract2011

Effect of water table level on greenhouse gas emissions from two cultivated peat soils in Sweden

Berglund, Örjan; Berglund, Kerstin

Abstract

A lysimeter method with undisturbed soil columns was used to investigate whether adjustment of the groundwater level could mitigate greenhouse gas (GHG) emissions from cultivated peat soils. The study was carried out using organic soils from two locations in Sweden: Örke, a typical cultivated fen peat with low pH and high organic matter content and Majnegården, a more uncommon fen peat type with high pH and low organic matter content. A drilling method with minimal soil disturbance was used to collect 12 undisturbed soil monoliths per site. The lysimeters were supplied with water from below and sown with ryegrass (Lolium perenne). The groundwater level was set to 40 cm or 80 cm below the surface. CO2, CH4 and N2O emissions from the lysimeters were measured weekly and complemented with incubation experiments with small undisturbed soil cores subjected to different tensions (5, 40, 80 and 600 cm water column). CO2 emissions were greater from the treatment with the water table level at 40 cm depth (446 mg m-2 h-1) compared with at 80 cm (393 mg m-2 h-1). N2O emissions peaked in springtime and CH4 emissions were very low or negative. Estimated GHG emissions during one year were between 2.70 and 3.55 kg CO2 equivalents m-2. Soil properties of the different soil layers determined the effect of groundwater regulation. Lowering the groundwater level only increases emission rates if new layers with easily decomposable material or low C/N ratios are exposed. The results from the lysimeter experiment were supported by the incubation experiment

Published in

NJF Report
2011, Volume: 7, number: 3, pages: 100-100

Conference

24th NJF Congress: Food, Feed, Fuel and Fun