Soil morphology

Soil morphology studies can make original contributions to the characterization of soil structure. Soil profile descriptions, as reviewed in chapter 1 , include a field evaluation of soil structure by noting sizes, shapes and degrees of development of natural aggregates (peds). Also, the occurrence of macropores formed by roots or soil animals is observed. This information is valuable, in principle, to improve soil sampling procedures for physical structure measurements, as discussed in chapter 2 . However, soil morphological studies can also contribute more specific, quantitative information by analysing soil thin sections or polished sections of plastic-impregnated, undisturbed soil samples. Recently, submicroscopic techniques have been developed that allow very detailed observations and chemical and mineralogical characterizations of soil compounds, as occurring in situ. Such techniques may be valuable for investigating structure stability.