Horizon identification using excel

Soil classifiers have taken their lead from biologists but have not produced an internationally accepted system even though the WRB is supported by the IUSS. More recently Mazaheri et al. (1995a, 1995b) have tried to introduce Fuzzy logic into soil classification. They achieved a small amount of success when their technique was applied to selected soils in Australia but failed when applied to other soils. Like most classifiers before them, they applied their technique to whole soils. Since soils are extremely variable and do not show homology of their constituent horizons (FitzPatrick 1988) more attention should be given to identifying horizons and less effort in trying to produce a hierarchical system for whole soils. Horizon Designation The underlying concept is that soil properties are coordinates, (Crowther, 1953) which intersect in space to create reference points (horizons) which can be thought of as forming a universe of points with varying distances one from the other. The horizons are arranged in groups based on one or more conspicuous properties. The groups are given names ending with 'on'. Thus all the pale coloured upper horizons form a group of albons with the symbol 'Ab'. The various individual horizons within the albons are given the symbols 'Aba', 'Abb', etc. At present it is not possible to apply this mathematically to all situations thus many of the groups are created subjectively. The system attempts to place unknown horizons within the universe of points based upon a calculated score within Excel. Thus the basic theoretical units are reference points, which have fixed values for each property created on coordinate principles. The identification is based on the concept of the closest match or Euclidian distance between the unknown and fixed reference values. It should be stressed that this system uses single fixed values and not value ranges as used in other systems. This allows a certain degree of overlap or fuzziness. These situations present many philosophical difficulties and also problems with regard to nomenclature. Should horizons be named on the basis of their polygenetic development? At this stage in the development of Pedology, it seems that an almost completely pragmatic approach should be adopted, based on the dominance of the property or properties of the horizons. These properties may be continuing to form at present or they may be inherited partially or completely from a previous phase of soil formation.