Soil trends in two valley fill sequences

Abstract

A sequence of profiles in alluvium from the South Coast of New South Wales and another from the Southern Tablelands are described and compared. Each sequence displays profiles of essentially sedimentary nature on low, narrow alluvial benches, cumulic soils on the more general flood-plain landscapes, soils with A and minimal texture B horizons on low terraces, and soils with strongly differentiated A and texture B horizons on high alluvial terraces. Profile development for each sequence is represented as depth functions and from these data indices of profile anisotropy (IPA) are derived. The step-wise changes in biotic and mineral profile organization from stratigraphically young to old soils are similar at both locations. Comparable profile sequences on ,alluvium have been observed in many other locations in humid south-eastern Australia. Available stratigraphic information at these locations is insufficient for estimates of rate of soil development to be made.