Nitrogen and dissolved organic carbon (DOC) losses from an artificially drained grassland on organic soils

Abstract

Abstract. -N) as well as dissolved organic carbon (DOC) and nitrogen (DON) concentrations and losses were studied for three and two years, respectively, in a small catchment dominated by a degraded peatland used as intensive grassland. Concentrations in the shallow groundwater were spatially and temporally very variable, with NO 3 -N being the most dynamic component . Ditch DOC concentration were lower than the groundwater DOC concentration of 50.6 ± 15.2 mg L −1 (14.9 to 88.5 mg L −1 ). Both DOC and N concentrations were governed by hydrological conditions, but NO 3 -N reacted much faster and clearer on rising discharge rates than DOC, which tended to be higher under drier conditions. In the third year of the study, the superposition of a very wet summer and land use changes from grassland to arable land in a part of the catchment suggests that, under re-wetting conditions with a high groundwater table in summer, NO 3 -N would diminish quickly, while DOC would remain on a similar level. Further intensification of the land use, on the other hand, would increase N losses to receiving water bodies.

The full carbon balance of a rewetted cropland fen and a conservation-managed fen

“…yr -1 S F B F ) are close to fluxes reported from some temperate 20 and boreal fens in Scandinavia and Canada (5 g C m -2 yr -1 , Strack et al, 2008;3.7 g C m -2 yr -1 , Juutinen et al, 2013) and German drained peat grasslands (5.2 g C m -2 yr -1 , Tiemeyer and Kahle, 2014), and are low compared to values from UK raised bogs (25 g C m -2 yr -1 , Dinsmore et al, 2010) and blanket bogs (33 g C m -2 yr -1 , Worrall et al, 2003). Other semi-natural and agricultural fens in the same region (East Anglia, UK), measured concurrently with our study, also had low DOC fluxes (4.1 7.9 g C m -2 yr -1 ), whilst semi-natural fens and peat grasslands in wetter parts of the UK had higher fluxes (Somerset; 10-22 g C m -2 yr -1 , Anglesey; 18-31 g C m -2 yr -1 ) (Evans et al, 2016a).…”

Hydrological controls on DOC : nitrate resource stoichiometry in a lowland, agricultural catchment, southern UK

“…This study, amongst others, has revealed significant differences in the relationship between DOC : nitrate and discharge dependent on both geology and seasonal effects (Tiemeyer and Kahle, 2014;Thomas et al, 2016). The Chalk site exhibited little variation in DOC : nitrate with discharge due to the dominance of groundwater contribution at both high and low flows.…”

Impact of fertiliser, water table, and warming on celery yield and CO2 and CH4 emissions from fenland agricultural peat

“…Peatlands subjected to drainage (such as agricultural peats) leach more DOC than undisturbed ones (Frank et al, 2014). Nevertheless, studies on peatland restoration present mixed results of rewetting on the concentration of DOC (Tiemeyer and Kahle, 2014;Frank et al, 2014;Preston et al, 2011;Schwalm and Zeitz, 2015).…”