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Study included seven soils, an adjacent spring and brook and was conducted to estimate CH(4) source and sink strengths of forest soils along a wetness gradient, i.e. their exchange with atmosphere ( direct emission), and hydrosphere ( indirect emission). Soils are represented by anaerobic Histosol, oxic Cambisols, Histosol with degraded peatlayers and Gleysols having intermediate redox state. They could be separated into three emission groups: CH(4) emitting ( 248 318 kg C ha(-1) a(-1)), CH(4...Study included seven soils, an adjacent spring and brook and was conducted to estimate CH(4) source and sink strengths of forest soils along a wetness gradient, i.e. their exchange with atmosphere ( direct emission), and hydrosphere ( indirect emission). Soils are represented by anaerobic Histosol, oxic Cambisols, Histosol with degraded peatlayers and Gleysols having intermediate redox state. They could be separated into three emission groups: CH(4) emitting ( 248 318 kg C ha(-1) a(-1)), CH(4) uptake (- 0.1 to - 5 kg C ha(-1) a(-1)), and soils on the edge of CH(4) uptake and release (- 0.2 - 20 kg C ha(-1) a(-1)). Although soils with CH(4) uptake were dominant (75%), the soil specific CH(4) budget identified the study field (6.53 ha) as CH(4) source (40.9 kg C ha(-1) a(-1)). Not only CH(4) emissions, but also dissolved CH(4) in soil solution varied regularly with soil type. Individual soil solutions contained 0.008 - 151 mu mol CH(4) l(-1). CH(4) vanished to negligible loads, when dissolved CH(4) passed an oxidative downslope soil zone, but promoted CH(4) uptake was measured at this soil. In turn, CH(4) was discharged to the atmosphere, when the soil solution left the pedosphere across an anaerobic soil zone. These measured indirect emissions were low (34 g C a(-1)), but the values of individual soil solution indicate possible higher discharges (3.9 kg a(-1)) at a different soil pattern. The results suggest that CH(4) uptake rates of temperate forests are overestimated. » weiterlesen» einklappen

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