Groundwater nitrate response to sustainable nitrogen management

Hansen, Birgitte; Thorling, Lærke; Termansen, Mette; Dalgaard, Tommy

doi:10.1038/s41598-017-07147-2

Cited by 173 publications

(113 citation statements)

References 45 publications

Supporting

Mentioning

108

Contrasting

Unclassified

Order By: Relevance

“…Eutrophication risk is defined by nitrogen application in coastal watersheds that exceeds 10 kg ha −1 and coastal groundwater discharge that exceeds 100 m 2 a −1 . The threshold value for nitrogen input corresponds to values that have historically led to strongly elevated nitrogen concentrations in groundwater in Europe and North America 39,40 that have contributed to the eutrophication of terrestrial and nearshore ecosystems 41 . Note that the lack of data outside of North America and Europe make the extrapolation uncertain, and the numbers reported here should be considered a first order estimate.…”

Section: Resultsmentioning

confidence: 99%

Fresh groundwater discharge insignificant for the world’s oceans but important for coastal ecosystems

2020

View full text Add to dashboard Cite

The flow of fresh groundwater may provide substantial inputs of nutrients and solutes to the oceans. However, the extent to which hydrogeological parameters control groundwater flow to the world's oceans has not been quantified systematically. Here we present a spatially resolved global model of coastal groundwater discharge to show that the contribution of fresh groundwater accounts for~0.6% (0.004%-1.3%) of the total freshwater input and~2% (0.003%-7.7%) of the solute input for carbon, nitrogen, silica and strontium. However, the coastal discharge of fresh groundwater and nutrients displays a high spatial variability and for an estimated 26% (0.4%-39%) of the world's estuaries, 17% (0.3%-31%) of the salt marshes and 14% (0.1-26%) of the coral reefs, the flux of terrestrial groundwater exceeds 25% of the river flux and poses a risk for pollution and eutrophication.

show abstract

Section: Resultsmentioning

confidence: 99%

Fresh groundwater discharge insignificant for the world’s oceans but important for coastal ecosystems

2020

View full text Add to dashboard Cite

show abstract

“…Hansen et al [12] found significant correspondence between developments in N surplus and nitrate concentrations in upper groundwater for four subsequent development periods for Danish agriculture in the period 1946-2012, and similarly for developments in the nitrogen use efficiency.…”

Section: Nitrogen Budgets and Relation To Water Qualitymentioning

confidence: 96%

Nitrogen Surplus—A Unified Indicator for Water Pollution in Europe?

Klages

Heidecke

Osterburg

et al. 2020

Water

Self Cite

View full text Add to dashboard Cite

Pollution of ground-and surface waters with nitrates from agricultural sources poses a risk to drinking water quality and has negative impacts on the environment. At the national scale, the gross nitrogen budget (GNB) is accepted as an indicator of pollution caused by nitrates. There is, however, little common EU-wide knowledge on the budget application and its comparability at the farm level for the detection of ground-and surface water pollution caused by nitrates and the monitoring of mitigation measures. Therefore, a survey was carried out among experts of various European countries in order to assess the practice and application of fertilization planning and nitrogen budgeting at the farm level and the differences between countries within Europe. While fertilization planning is practiced in all of the fourteen countries analyzed in this paper, according to current legislation, nitrogen budgets have to be calculated only in Switzerland, Germany and Romania. The survey revealed that methods of fertilization planning and nitrogen budgeting at the farm level are not unified throughout Europe. In most of the cases where budgets are used regularly (Germany, Romania, Switzerland), standard values for the chemical composition of feed, organic fertilizers, animal and plant products are used. The example of the Dutch Annual Nutrient Cycling Assessment (ANCA) tool (and partly of the Suisse Balance) shows that it is only by using farm-specific “real” data that budgeting can be successfully applied to optimize nutrient flows and increase N efficiencies at the farm level. However, this approach is more elaborate and requires centralized data processing under consideration of data protection concerns. This paper concludes that there is no unified indicator for nutrient management and water quality at the farm level. A comparison of regionally calculated nitrogen budgets across European countries needs to be interpreted carefully, as methods as well as data and emission factors vary across countries. For the implementation of EU nitrogen-related policies—notably, the Nitrates Directive—nutrient budgeting is currently ruled out as an entry point for legal requirements. In contrast, nutrient budgets are highlighted as an environment indicator by the OECD and EU institutions.

show abstract

“…The production of biomass in each scenario is based on an extensive set of agricultural statistics on crop productivity and land use that have been used to estimate the productivity of all relevant crops for 2020 [7,10]. The basis for these estimates is, in line with previous studies of decadal trends in Danish agriculture [7,11], a linear extrapolation of present crop productivity as well as literature values when accurate statistics were not available. Underlying model assumptions and data references are further explained in the supplementary information.…”

Section: Methodsmentioning

confidence: 99%