Abstract
Throughout the world, nitrogen (N) losses from intensive agricultural production may end up as undesirably high concentrations of nitrate in groundwater with a long-term impact on groundwater quality. This has human and environmental health consequences, due to the use of groundwater as a drinking water resource, and causes eutrophication of groundwater-dependent ecosystems such as wetlands, rivers and near-coastal areas. At national scale, the measured nitrate concentrations and trends in Danish oxic groundwater in the last 70 years correlate well with the annual agricultural N surpluses. We also show that the N use efficiency of agriculture is related to the groundwater nitrate concentrations. We demonstrate an inverted U-shape of annual nitrate concentrations as a function of economic growth from 1948 to 2014. Our analyses evidence a clear trend of a reversal at the beginning of the 1980s towards a more sustainable agricultural N management. This appears to be primarily driven by societal demand for groundwater protection linked to economic prosperity and an increased environmental awareness. However, the environmental and human health thresholds are still exceeded in many locations. Groundwater protection is of fundamental global importance, and this calls for further development of environmentally and economically sustainable N management in agriculture worldwide.
Highlights
Today more than half of the world’s population is nourished by agricultural outputs that have been produced using artificial fertilizers[1,2,3]
Protection of groundwater is of fundamental global importance due to its many uses, for example as drinking water and in industrial and agricultural productions, and because of its environmental value for groundwater-dependent ecosystems such as wetlands, rivers and near-coastal areas[9]
The groundwater and drinking water standards are set to a maximum of 50 mg l−1 nitrate in the European Union (EU) following the recommendations of WHO10, which is almost equal to the US Environmental Protection Agency’s maximum contaminant level of 10 mg l−1 N11
Summary
Birgitte Hansen[1], Lærke Thorling[1], Jörg Schullehner 1, Mette Termansen2 & Tommy Dalgaard[3]. Throughout the world, nitrogen (N) losses from intensive agricultural production may end up as undesirably high concentrations of nitrate in groundwater with a long-term impact on groundwater quality This has human and environmental health consequences, due to the use of groundwater as a drinking water resource, and causes eutrophication of groundwater-dependent ecosystems such as wetlands, rivers and near-coastal areas. We use measurements of nitrate in Danish groundwater representing the past 70 years to analyse the N sustainability of intensive agricultural N management in relation to groundwater protection and economic growth This type of analysis has previously been applied to other environmental quality indicators[2, 31], but to our knowledge this has not been done for long-term groundwater nitrate measurements
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call