 |
| Titel |
Regional analysis of groundwater nitrate concentrations and trends in Denmark in regard to agricultural influence |
| VerfasserIn |
B. Hansen, T. Dalgaard, L. Thorling, B. Sørensen, M. Erlandsen |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 8 ; Nr. 9, no. 8 (2012-08-23), S.3277-3286 |
| Datensatznummer |
250007247
|
| Publikation (Nr.) |
 copernicus.org/bg-9-3277-2012.pdf |
|
|
|
|
|
| Zusammenfassung |
| The act of balancing between an intensive agriculture with a high potential
for nitrate pollution and a drinking water supply almost entirely based on
groundwater is a challenge faced by Denmark and similar regions around the
globe. Since the 1980s, regulations implemented by Danish farmers have
succeeded in optimizing the N (nitrogen) management at farm level. As a
result, the upward agricultural N surplus trend has been reversed, and the N
surplus has reduced by 30–55% from 1980 to 2007 depending on region. The
reduction in the N surplus served to reduce the losses of N from
agriculture, with documented positive effects on nature and the environment
in Denmark. In groundwater, the upward trend in nitrate concentrations was
reversed around 1980, and a larger number of downward nitrate trends were
seen in the youngest groundwater compared with the oldest groundwater.
However, on average, approximately 48% of the oxic monitored groundwater
has nitrate concentrations above the groundwater and drinking water
standards of 50 mg l−1. Furthermore, trend analyses show that 33% of all
the monitored groundwater has upward nitrate trends, while only 18% of
the youngest groundwater has upward nitrate trends according to data sampled
from 1988–2009. A regional analysis shows a correlation between a high level
of N surplus in agriculture, high concentrations of nitrate in groundwater
and the largest number of downward nitrate trends in groundwater in the
livestock-dense northern and western parts of Denmark compared with the
southeastern regions with lower livestock densities. These results indicate
that the livestock farms dominating in northern and western parts of Denmark
have achieved the largest reductions in N surpluses. Groundwater recharge
age determinations allow comparison of long-term changes in N surplus in
agriculture with changes in oxic groundwater quality. The presented data
analysis is based on groundwater recharged from 1952–2003, but sampled from
1988–2009. Repetition of the nitrate trend analyses at five-year intervals
using dating of the groundwater recharged in the coming years and a longer
time series of the nitrate analyses can reveal the evolution in nitrate
leaching from Danish agriculture during the past 10 yr. Similar analyses
can be carried out to compare with other regions internationally. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|