Developing the First City-wide Map of Soil Associations
Aey (1991) wrote a guide on how to prepare a Concept Map of Soil Associations for the entire city. This guide was based on: the method described by Grenzius (1987) for preparing a Soil Association Map for West Berlin, and the Map of Soil Associations by Grenzius, which was transferred into the spatial reference system of the Urban and Environmental Information System (Informationssystem Stadt und Umwelt, ISU) by Fahrenhorst, Haubrok, and Sydow (1990). No Soil Association Map of this or a similar kind existed for East Berlin. The bases for the development of the soil association map of West Berlin were the excavations and drilling stock samples conducted in all of West Berlin. These were conducted in forest plantations and agricultural areas under consideration of geomorphological-hydrological conditions, and, in populated areas, under consideration of uses. All basis rock and most uses, with the exception of industrial areas, were surveyed several times, and appropriate soil-scientific mapping was carried out. Based on the analysis of this mapping, conclusions were derived for soil conditions in unmapped areas.
The comprehensive soil-scientific studies used for the Map of Soil Associations in West Berlin have verified the Soil Map for many areas, such as forest and agricultural areas (farmland). The map is only verified partially, however, for areas linked to fewer soil-scientific studies. Such detailed soil mapping for East Berlin, however, only existed for forests. The present map is thus to be regarded as a verified map only for these areas and as a concept map for all remaining areas. Mappings for further individual areas were added at a later stage. All derivations and determinations of soil associations for East Berlin – excluding forests – had to be derived from existing material, such as geologic and topographic maps, soil maps, and data on land use, etc. The accuracy, content, and age of this material varied greatly.
More precise classification models for soil associations, as well as the definition of new soil associations not described by Grenzius, were enabled both by maps and soil studies conducted in West Berlin after the publication of the West Berlin Soil Association Map, and existing soil maps for East Berlin, particularly for forest areas.
Since a scale of 1 : 50,000 does not allow the spatial distribution of individual soil types to be differentiated in sufficient detail, Grenzius’ methodology for soil associations was retained which involves the selection of unifying geomorphological units. Soils of spatial and material coherence are combined as soil associations.
In conclusion, the whole map should be considered a Concept Map with some verified areas (partially verified concept map) only, which exclusively focuses on pervious soils.
The naming of the soil associations was based on the interactions of characteristic soils. The first and last soil of each soil association were specified, and, usually, one of the soils that characterizes material translocations (Grenzius 1987). This interacting system, or the link between soils in areas still extensively near-natural is characterized in the map legend by “-”.
Near-natural soils are found only in loosely populated areas.
The structures of soils in populated areas have sometimes been greatly altered by human intervention. These anthrosols appear randomly next to each other and are connected in the legend by “+”.
The legend is structured according to the degree of anthropogenic influence on and alterations of the soil. Near-natural soil associations are listed at the beginning; first the terrestrial soils, followed by the semi-terrestrial soils. Soil associations of anthropogenic aggradations and erosion are listed at the end. (Translator’s note: “aggradation” describes soils and materials which have been placed somewhere by natural processes (glaciers, water flows) or human actions. Anthropogenic aggradations include deep landfills (waste and debris depots, etc.), and shallow landfill of upper layers (playgrounds, building construction sites, street construction, etc.))
Borders were drawn between soil associations following reliefs in ridges and sinks. Neighbouring units can hence display the same starting and concluding elements. The area delineation of soil associations also had to conform to the Berlin Digital Spatial Reference System based on block and block segment areas of homogeneous use. If this process led to great losses of information, particularly in non-built-up and loosely built-up areas such as forests, agricultural areas, and settled areas with low degrees of impervious soil coverage, these block map areas were divided further, according to the borders of the soil associations. The decisive factors in these cases were the borders of geomorphological and geological units, contour lines, soil types (detail map), and aggradation borders. The factors for the delineation of anthropogenic soil associations were land use and the borders of aggradation or erosion. The further subdivision of soil associations thus directly influences the formation of block segments in block maps 1 : 5,000 and 1 : 50,000 (ISU5 and ISU50, Spatial Reference Environmental Atlas) and their continuous updates.
Near-natural and Anthropogenic Soil Associations
Determining factors for soil development are parent material, prevailing soil type, relief (slope, sink, channel, gradient etc.), water and climate conditions, as well as the degree of human influence. Anthropogenic influences are characterized by aggradation of natural soil material and non-natural materials (e.g. war debris, construction debris, slag and cinders), and erosion of natural soil. Important measures for anthropogenic alterations in soil include present and previous use, and the degree of impervious soil coverage. The map only shows pervious soils, independent of the degree of impervious soil coverage. The latter is used only to support the analysis of the degree of anthropogenic alterations of pervious soils in this area.
Near-natural soil associations are characterized by typical soil types, geomorphological structures, substrate/ soil types, and the influence of water. There are few alterations caused by humans.
The soil structure and soil associations of anthropogenic soil associations are not influenced by the topographical relief but rather by type of use, as well as the occurrence and type of aggradations. Some transitional forms still retain the characteristics of parent material, geomorphology, groundwater levels, and some natural soils. This is the case at military training areas, former surface mining sites, cemeteries, and levelled sewage farms.
Tab. 4 presents the effects human intervention has on soils. It classifies the urban area into various soil association categories (anthropogenic soil associations) under consideration of historic and current uses, damage to buildings in the Second World War, the type of construction, and the degree of impervious soil coverage.