Abstract

Long-term monitoring data from catchments with relatively uniform land use is important in order to cover management needs such as implementation of various EU Directives. This paper in a uniform fashion examines the temporal trends in nitrogen (N) concentrations and losses from agricultural catchments in the Nordic and Baltic countries. Thirty-five (35) catchments (range 0.1-33km2) in Norway (9), Denmark (5), Sweden (8), Finland (4), Estonia (3), Latvia (3) and Lithuania (3) were selected for this study. The longest time series were 23 years (1988-2010), while the shortest one was 10 years (2002-2011). The monthly nitrogen concentration and loss data series were tested for statistical trends (p<0.05; two-sided test) using the partial Mann-Kendall (PMK) test with stream discharge as an explanatory variable. The study results show a large variation in nitrogen concentrations and losses among the studied catchments, with a large interannual variability in all catchments. For nitrogen losses, 11 statistically significant trends were detected. Nine of these were downward (four out of five Danish catchments; four out of eight in Sweden; one out of three in Finland). Upward trends were detected in two catchments (one in Estonia and one in Latvia). For nitrogen concentrations, 13 statistically significant trends were detected. 10 of these were downward. Among the 11 catchments that showed trends in nitrogen losses, nine catchments also showed statistically significant trends in the in-stream concentration series. In addition, three more Swedish catchments showed downward trends in the concentration series, and one Estonian catchment showed an upward trend. These results indicate that targeted strategies towards reduced nitrogen losses from agricultural land (as in the case of Denmark and Sweden) may significantly improve nutrient surface water quality in small agricultural catchments.

Keywords

Agricultural streams; Baltic region; Concentrations; Losses; Monitoring; Nitrogen; Temporal trends

Published in

Agriculture, Ecosystems and Environment
2014, Volume: 198, pages: 94-103
Publisher: Elsevier Masson

SLU Authors

• Kyllmar, Katarina

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

Associated SLU-program

Eutrophication
Agricultural landscape


Sustainable Development Goals

SDG6 Ensure availability and sustainable management of water and sanitation for all


UKÄ Subject classification

Environmental Sciences related to Agriculture and Land-use


Publication identifier

DOI: https://doi.org/10.1016/j.agee.2014.03.028

Permanent link to this page (URI)

https://res.slu.se/id/publ/65069