Monitoring sites - selection of fields
Selection of fields
The leaching assessment programme originally encompassed six fields in the size range 1-3 ha. It was necessary to reduce the number to five as of 1 July 2003. The fields were selected so as to represent various types of geology. Two of the fields are located on sandy deposits of coarse and fine sand, respectively. The remaining sites are located on clayey deposits. The clayey fields were required to have a well-defined drainage system that covered the whole field and only that field. The groundwater table is reasonably close to the surface at all the sites (2-5 m b.g.s.).
Selection of the clayey fields was made difficult by the fact that the individual fields had to be drained by a well-known and well-defined drainage system. In order to achieve this it was necessary to construct a border drain and change the drains around the outflow. Excavation work was not permitted on the field itself from where the water samples are collected.
More detail about the individual fields can be obtained by clicking the location names on the map.
The sites were chosen so as to take into account the climatic variation in Denmark, especially the variation in precipitation. Based on annual mean precipitation, one sandy and two clayey sites are located in areas with relatively high precipitation, while the remaining sites are located in areas where the precipitation is lower than the mean.
The test fields have been thoroughly characterized as regards soil profiles, geology and hydrogeology. The soil and geological conditions have been described in sufficient detail to enable the leaching conditions to be modelled.
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