denitrification from the root zone to streams
DESCRIPTION
Plant Congress 2006 January 10 and 11, 2006. Denitrification from the root zone to streams. Gitte Blicher-Mathiesen NERI Department of Freshwater Ecology. Nitrate reduction from the root zone to the sea. Nitrate reduction: about 100.000 tonnes N/year - PowerPoint PPT PresentationTRANSCRIPT
National Environmental Research Institute
Denitrification from the root zone to streams
Gitte Blicher-Mathiesen
NERI
Department of Freshwater Ecology
Plant Congress 2006 January 10 and 11, 2006
National Environmental Research Institute
Nitrate reduction from the root zone to the sea
• Nitrate reduction: about 100.000 tonnes N/year
• Nitrate leaching from the root zone: 168.000 tonnes N/year
• N run off to the sea: 67.000 tonnes N/year
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Nitrate reduction occurs
• in aquifers• in wetlands and riparian areas• in the stream bottom• during water transport in streams and
lakes
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% N-retention
n_ret_1dec
< 20.0
20 - 25
25 - 30
30 - 35
35 - 40
40 - 45
45 - 50
50 - 55
55 - 60
60 - 63
N-retention (%) i 26 catchments
FromFYNS AMT
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Measured N-reduction inRiparian Areas
Study site Reduction(kg N/ha/year)
N-retention(%)
River Stevns 57 97
Rabis brook 398 56
River Gjern,4 meadows and fen 42 – 2,179 67-99
River Brede 92 71 (Hoffmann, 1998)
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Measured N-reduction i Riparian Areas, irrigated with drain - or stream water
Study site Reduction(kg N/ha/year)
N-retention(%)
Glumsø, reed forest* 520-2,725 54-65
River Stevns 350 99
Syv brook 300 72
River Store 530 48
River Gjern* 30-196 90-98
* Study with variable hydraulic load (Hoffmann, 1998)
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Outline of groundwater flow through riparian areas
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Riparian area
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Conclusion• N-reduction for DK about 100.000 tonnes N per y
• N-retention between root zone and streams
– sandy catchments 38 - 89 %
– loamy catchments 12- 47 %
– geology, discharge, tile drainage, lakes and wetlands/riparian areas
• Riparian areas
– reduction 32 - 2,100 kg N/ha/year
– N-load, geology, groundwater flowpath