NUMERICAL ANALYSIS OF SOILS: A COMPARISON OF THREE SOIL PROFILE MODELS WITH FIELD CLASSIFICATION

Summary Fourteen field and laboratory attributes of 49 south‐east Queens land soils were examined by numerical analysis. Three different models were used for description: the soils were viewed (1) as arrays of layer‐attributes, (2) as sets of depth functions (orthogonal polynomials) each of which describes an attribute, and (3) as sequences of layers of soil material. Dendrograms derived from Euclidean distance similarity matrices were constructed for the 49 profiles. Very similar dendrograms were obtained using (a) layer‐by‐layer comparisons (with layers weighted by an exponential depth function) and (6) orthogonal polynomials, with equal weight given to profile mean (size parameter) and five coefficients (shape parameters). The dendrogram derived from sequential analysis differed markedly from the others and seemed less meaningful; the divisive approach that had to be adopted to delineate groups of profile‐layers may have resulted in a sub‐optimal classification. An independent field study which related the soils to geomorphic units and to differences in parent material provided a further, separate classification. The groups derived by numerical analysis, using models I and 2, agreed well with the field classes even though the strategies used were different and independent. It is concluded that existing techniques of numerical analysis can provide immediate useful support in field surveys.