Riparian Lowlands in Clay Till Landscapes Part II: Nitrogen Reduction and Release Along Variable Flow Paths
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Riparian Lowlands in Clay Till Landscapes Part II : Nitrogen Reduction and Release Along Variable Flow Paths. / Petersen, R. J.; Prinds, C.; Jessen, S.; Iversen, B. V.; Kjaergaard, C.
In: Water Resources Research, Vol. 56, No. 4, e2019WR025810, 2020.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Riparian Lowlands in Clay Till Landscapes Part II
T2 - Nitrogen Reduction and Release Along Variable Flow Paths
AU - Petersen, R. J.
AU - Prinds, C.
AU - Jessen, S.
AU - Iversen, B. V.
AU - Kjaergaard, C.
PY - 2020
Y1 - 2020
N2 - Riparian lowlands are known to control catchment nitrogen (N) balances. This study examined the role of agricultural tile drainage systems, often present in clay till landscapes, on the transport, transformation, and mass balance of N species in four riparian peat lowland transects receiving agricultural tile drainage water. Monitoring of N speciation of drain, stream, and groundwater, combined with a previously established water balance, enabled the determination of N mass balances for different flow paths including groundwater, subsurface drain water, and overland flow for each piezometer transect. The type of overland flow largely affected nitrate-N (NO3-N) removal efficiency, as determined by the total N output from a transect relative to the NO3-N loading (%). Infiltration and subsurface flow followed by exfiltration (short return flow) allowed an efficient removal of NO3-N (71–94%), while direct overland flow strongly lowered NO3-N removal (25%) in one transect. The hydraulic loading rate versus the lowland infiltration capacity determined the transport pathways and thus the resulting NO3-N removal efficiency. For all transects there was a net export of organic N and/or ammonium, associated with in situ N release from peat decomposition, through overland flow and groundwater discharge. These exports partly counterbalanced NO3-N removal and significantly reduced the overall total N removal for the riparian lowlands. However, the N removal efficiencies remained positive (1–56%). The study indicates that N budgets for riparian lowlands need to account for overland flow as a transport pathway for N.
AB - Riparian lowlands are known to control catchment nitrogen (N) balances. This study examined the role of agricultural tile drainage systems, often present in clay till landscapes, on the transport, transformation, and mass balance of N species in four riparian peat lowland transects receiving agricultural tile drainage water. Monitoring of N speciation of drain, stream, and groundwater, combined with a previously established water balance, enabled the determination of N mass balances for different flow paths including groundwater, subsurface drain water, and overland flow for each piezometer transect. The type of overland flow largely affected nitrate-N (NO3-N) removal efficiency, as determined by the total N output from a transect relative to the NO3-N loading (%). Infiltration and subsurface flow followed by exfiltration (short return flow) allowed an efficient removal of NO3-N (71–94%), while direct overland flow strongly lowered NO3-N removal (25%) in one transect. The hydraulic loading rate versus the lowland infiltration capacity determined the transport pathways and thus the resulting NO3-N removal efficiency. For all transects there was a net export of organic N and/or ammonium, associated with in situ N release from peat decomposition, through overland flow and groundwater discharge. These exports partly counterbalanced NO3-N removal and significantly reduced the overall total N removal for the riparian lowlands. However, the N removal efficiencies remained positive (1–56%). The study indicates that N budgets for riparian lowlands need to account for overland flow as a transport pathway for N.
KW - Denitrification
KW - Nitrate
KW - Nitrogen
KW - Overland flow
KW - Riparian lowlands
KW - Wetlands
U2 - 10.1029/2019WR025810
DO - 10.1029/2019WR025810
M3 - Journal article
AN - SCOPUS:85079246013
VL - 56
JO - Water Resources Research
JF - Water Resources Research
SN - 0043-1397
IS - 4
M1 - e2019WR025810
ER -
ID: 243066415