Mapping nitrate leaching to upper groundwater in the sandy regions of The Netherlands, using conceptual knowledge.

The European Community asks its Member States to provide a comprehensive and coherent overview of their groundwater chemical status. It is stated that simple conceptual models are necessary to allow assessments of the risks of failing to meet quality objectives. In The Netherlands two monitoring networks (one for agriculture and one for nature) are operational, providing results which can be used for an overview.

Nitrate leaching in agriculture to upper groundwater in the sandy regions of the Netherlands during the 1992-1995 period.

The Dutch National Monitoring Programme for Effectiveness of the Minerals Policy (LMM) was initiated to allow detection of a statutory reduction in nitrate leaching caused by a decreasing N load. The starting point, or baseline, was taken as the nitrate concentration of the upper metre of groundwater sampled on 99 farms in the 1992-1995 period in the sandy areas of the Netherlands, where predominantly grass and maize grow. We found here that a reduction in nitrate leaching of more than 20% in future would almost certainly be detected with the LMM.

Nitrate leaching by atmospheric N deposition to upper groundwater in the sandy regions of The Netherlands in 1990.

Anthropogenic increase in atmospheric nitrogen (N) deposition in nature areas results in nitrate leaching to groundwater, threatening its quality. Member states of the European Union are obliged to reduce groundwater nitrate concentrations and to monitor this reduction. The relationship between N deposition and groundwater nitrate concentrations is quantified using a field survey and geographical information.