Spatial and temporal variation of methane emissions in drained eutrophic peat agro-ecosystems: drainage ditches as emission hotspots

Abstract

Our research investigates the spatial and temporal variability of methane (CH 4 ) emissions in two drained eutrophic peat areas (one intensively managed and the other less intensively managed) and the correlation between CH 4 emissions and soil temperature, air temperature, soil moisture content and water table. We stratified the land-5 scape into landscape elements that represent different conditions in terms of topography and therefore differ in moisture conditions. There was great spatial variability in the fluxes in both areas; the ditches and ditch edges (together 27% of the landscape) were methane hotspots whereas the dry fields had the smallest fluxes. In the intensively managed site the fluxes were significantly higher by comparison with the less 10 20 on groundwater level, soil moisture content, temperature, and grassland management (Blodau and Moore, 2003; Christensen et al., 2003; Hendriks et al., 2007; Hargreaves and Fowler, 1998; Pelletier et al., 2007; Van den Pol-Van Dasselaar et al., 1998a). CH 4 emissions are difficult to estimate because of their large spatial and temporal variability. Furthermore, there are two major challenges when upscaling: selecting the correct 25 ecosystem variables for the stratification and developing predictive relationships (Groffman et al. Abstract IntroductionConclusions References Tables tensively managed) are located in a polder in the west of the Netherlands (Coord. Abstract Introduction Conclusions ReferencesTables 20 abundant.The Oukoop experimental plots are situated on an intensive dairy farm. The management regime varies per year, but overall consists of mowing three times a year and manuring and fertilizing three times a year. The average C and N contents in the top 20 cm of the soil are 24% and 2.4%, respectively. Here too, Lolium perenne is the most 25 dominant species and Poa trivialis is co-dominant.

Assessing greenhouse gas emissions from peatlands using vegetation as a proxy

“…Emissions from ditches can be substantial (Van den Pol-Van Dasselaar et al, 1999;Schrier-Uijl et al, 2008;Maljanen et al, 2010) but were neglected, as the ditches cover only small areas (1.8% of the total area in Ostrovskoe and 1.1% in Vygonoshanskoe). Moreover, ditches are expected to be overgrown after In order to estimate emission reductions, scenarios of vegetation development (based on literature and expert judgement) and associated emissions for the next 30 years were formulated for the situation with rewetting ('project scenario') and the situation without rewetting ('baseline scenario').…”

Peatlands and the carbon cycle: from local processes to global implications – a synthesis

“…In wetter fens, particularly when there is significant cover of sedges, the annual flux can exceed 15 g C m −2 yr −1 (Shurpali et al, 1993;Suyker et al, 1996). In a boreal landscape, Bubier et al (2005) estimated a regional CH 4 flux of 7 g C m −2 yr −1 , but the fluxes from individual peatlands types differed by a factor 10 or more (see also Schrier et al, 2008). Back calculating from the recent estimates of the atmospheric burden of CH 4 from high latitude wetlands (8-20×10 12 g CH 4 yr −1 , Mikaloff Fletcher et al, 2004;Chen and Prinn, 2006) yields an average emission of 2-5 g C m −2 yr −1 .…”

Trade-off in ecosystem services of the Somerset Levels and Moors wetlands

“…However, what is not factored into these calculations are potential CH 4 emissions from the 200 km of drainage ditches that criss-cross the Somerset Levels. The limited available literature suggests that these ditches could be CH 4 emission hotspots (Van Den Pol-Van Dasselaar et al 1998, Schrier-Uijl et al 2008. Any future research in the SLM should commit to reducing the uncertainty in estimates of catchment CH 4 emissions through incorporating these less dominant but nevertheless potentially important locations.…”