Content area
Full Text
Water Air Soil Pollut (2013) 224:1440 DOI 10.1007/s11270-013-1440-5
Rewetting Drained Peat Meadows: Risks and Benefitsin Terms of Nutrient Release and Greenhouse Gas Exchange
B. P. van de Riet & M. M. Hefting &
J. T. A. Verhoeven
Received: 30 March 2012 /Accepted: 10 January 2013 /Published online: 8 March 2013 # Springer Science+Business Media Dordrecht 2013
Abstract Rewetting of agriculturally used peatlands has been proposed as a measure to stop soil subsidence, conserve peat and rehabilitate ecosystem functioning. Unintended consequences might involve nutrient release and changes in the greenhouse gas (GHG) balance towards CH4-dominated emission. To investigate the risks and benefits of rewetting, we subjected soil columns from drained peat- and clay-covered peatlands to different water level treatments: permanently low, permanently inundated and fluctuating (first inundated, then drained). Surface water and soil pore water chemistry, soil-extractable nutrients and greenhouse gas fluxes were measured throughout the experiment. Permanent inundation released large amounts of nutrients into pore water, especially phosphorus (up to 11.7 mg P-PO4 l1) and ammonium(4.8 mg N-NH4 l1). Phosphorus release was larger in peat than in clay soil, presumably due to the larger pool of iron-bound phosphorus in peat. Furthermore,
substantial amounts of phosphorus and potassium were exported from the soil matrix to the surface water, risking the pollution of local species-rich (semi-)aquatic ecosystems. Rewetting of both clay and peat soil reduced CO2 emissions. CH4 emissions increased, but, in contrast to the expectations, the fluxes were relatively low. Calculations showed that rewetting reduced net cumulative GHG emissions expressed as CO2 equivalents.
Keywords Fen rewetting . P mobilisation . Ammonium . Methane . Carbon dioxide
1 Introduction
Drainage of peatlands results in soil degradation, peat oxidation and concomitant emissions of CO2 to the atmosphere (Veenendaal et al. 2007; Renger et al. 2002). In the past decades, intensification of agricultural land use has progressively accelerated these processes, thereby causing high rates of peat subsidence up to 2 cmyear1
(Dawson et al. 2010; Van den Akker et al. 2008; Renger et al. 2002). Predicted climate change effects, such as sea level rise and extreme rainfall and drought events (IPCC, 2007), have spurred governments to consider adaptations of current land use and water management policies (VROM 2006; Kratz and Pfadenhauer 2001). One of the approaches under consideration is...