Pedogeomorphic aspects of the Roodepoort area, Transvaal: Soil depth-slope relationships

Abstract

Fifty hillslope profiles with associated soils in the Roodepoort area, Transvaal, were examined to determine the relationships between soil depth and hillslope characteristics. A meso-scale approach was adopted which implied the relationship between three soil depth phases and the hillslope units on a scale of 1:10 000. Although anomalies occur, it was found with the aid of statistical techniques, that a definite trend exists between soil depth and slope gradient. For the less than 8% slope class, soil depth variations could be ascribed to differences in parent rock and position in the landscape, whereas for slopes steeper than 8% slope, gradient apparently becomes the dominant determinant of the shallow soil depth. Because the soil depth-hillslope relationships were sufficiently well established by this study, it enabled the construction of three models to represent the varied conditions of the Roodepoort area.