Spatial pattern and variability of soils in a granite landscape, north-east of Nelspruit

Abstract

Morphological and selected chemical and granulometric properties of eleven soil profiles occurring on five hillslope sites (midslope, upper footslope, mid-footslope, lower footslope and valley bottom) were determined in order to evaluate the spatial pattern and variability of soils in a granitic area north-east of Nelspruit. A transect design was employed to compare the variance of selected soil properties within and between hillslope positions. Although a drainage-toposequence had developed in the colluvial deposits on the footslope, this soil pattern was interrupted in mid-footslope by sands of the Longlands form encountered between sands of the Avalon form. Meso-scale deflections of the bedrock floor in the form of hillslope terraces were presumably responsible for this variation in soil pattern. To study soil variability statistically, a two-stage nested design and an analysis of variance were employed. Although few significant results were obtained, certain tendencies were evident which pointed to a high degree of variability in selective soil properties in this landscape. Notwithstanding these findings, most of the spatial variability in soil properties could be explained in terms of pedogeomorphic processes.