Soil sample bench

This is a systematic and permanent collection of the Geological Service NRW (GD NRW) of representative soil samples for the documentation of the material actual state at the time of sampling and for the verification of analytical methods. Since 1990, a soil sample bank has been set up at the NRW Geological Service for long-term documentation of soil condition in North Rhine-Westphalia. Soil samples are stored here, which are taken from excavations up to 2 m depth for soil mapping. This includes all samples taken for soil status survey in the forest (BZE) in North Rhine-Westphalia. From the 80s and partly from previous years, many samples have already been available. These are an important foundation for the nationwide collection of soil samples. Soil samples can be specimens. For example, environmental changes must be demonstrated by comparing the test results of different old soil samples from the same test point. Therefore, it is particularly important to document the original sample well in order to find its collection point as accurately as possible in the terrain. A deviation of a few meters — but certainly some 100 m — can make a technically justifiable comparison impossible due to the natural heterogeneity of soils and the base geological substrate of soil formation. However, since there are always certain errors in determining the location in the terrain, for example in the forest, it is all the more important to describe the sampled soil (the soil type, the horizons, the soil types, the soil colors, the extraction depths, etc.) as precisely as possible. The comparability of follow-up examinations can thus be significantly improved. The soil sample bank not only helps to detect environmental changes in the soil, it also serves the ongoing work of the soil scientists at the Geological Service NRW; for many scientific questions, it may be important to use older soil samples for comparison. The question of, for example, to what extent a new analytical method is comparable to an old one can only be assessed if the same samples or sample series are examined according to the old and the new laboratory methods. New laboratory techniques also make it possible to examine parameters that previously appeared without relevance or could not be detected. In order to provide a representative comparison of the total land area, samples must be taken nationwide and with as regular distribution as possible. It is also important to ensure that geological base substrates are adequately represented. This is the only way to represent the geogenic and pedogenic aspects in addition to the regional ones. However, the value of a well-documented soil sample bank is based not least on the fact that sufficient material is available. The capacities are naturally limited. Currently, around 50,000 samples of approximately 250 ml volume can be stored in the soil sample bank of the Geological Service NRW.