Abstract
Leaching of nitrate (NO3) from agricultural areas in Denmark can lead to excess nitrogen (N) concentration in ground- and surface waters. However, during transport to the sea, NO3 can be removed through denitrification, a microbial process which converts NO3 into dinitrogen (N2) with a risk of producing smaller amounts of nitrous oxides (N2O). How much NO3 that is removed by denitrification in streams and during flooding of riparian areas is uncertain.
Therefore, to accurately predict this process will be an advantage for understanding N-cycling.
We used the Nitrogen Isotope Pairing Technique (Nielsen,1992; Audet et al, 2021) to measure denitrification in 15 streams and during periods with flooding of 3 riparian areas during a year constituting a dataset of 342 individual measurements. The denitrification rates found were 0.25±0.11 kg N ha-1 d-1 (winter half-year) and 0.57±0.14 kg N ha-1 d-1 (summer half-year) in streams, and 0.21 kg N ha-1 d-1 on the flooded riparian areas.
With streams stretching 83,183 km covering a surface area of 24,000 ha, the potential for Nretention is about 3500 tons N per year on a national scale. Considering that more than 95 % of the Danish streams have been channelized (Brookes, 1987), re-meandering streams and thereby increasing stream length, could possibly increase N retention substantially, making it a useful tool in limiting N leaching to the aquatic environment and coastal areas. Furthermore,
allowing the temporary inundation of riparian areas by restoring natural hydrology could contribute significantly to reducing nitrogen losses.
Therefore, to accurately predict this process will be an advantage for understanding N-cycling.
We used the Nitrogen Isotope Pairing Technique (Nielsen,1992; Audet et al, 2021) to measure denitrification in 15 streams and during periods with flooding of 3 riparian areas during a year constituting a dataset of 342 individual measurements. The denitrification rates found were 0.25±0.11 kg N ha-1 d-1 (winter half-year) and 0.57±0.14 kg N ha-1 d-1 (summer half-year) in streams, and 0.21 kg N ha-1 d-1 on the flooded riparian areas.
With streams stretching 83,183 km covering a surface area of 24,000 ha, the potential for Nretention is about 3500 tons N per year on a national scale. Considering that more than 95 % of the Danish streams have been channelized (Brookes, 1987), re-meandering streams and thereby increasing stream length, could possibly increase N retention substantially, making it a useful tool in limiting N leaching to the aquatic environment and coastal areas. Furthermore,
allowing the temporary inundation of riparian areas by restoring natural hydrology could contribute significantly to reducing nitrogen losses.
| Originalsprog | Engelsk |
|---|---|
| Publikationsdato | 2024 |
| Status | Udgivet - 2024 |
| Begivenhed | N Workshop: Resolving the Global Nitrogen Dilemma - Opportunities and Challenges - Lakeside Lecture Theaters at Aarhus University, Aarhus, Danmark Varighed: 17 jun. 2024 → 21 jun. 2024 https://conferences.au.dk/nworkshop |
Workshop
| Workshop | N Workshop |
|---|---|
| Lokation | Lakeside Lecture Theaters at Aarhus University |
| Land/Område | Danmark |
| By | Aarhus |
| Periode | 17/06/2024 → 21/06/2024 |
| Internetadresse |